OpenCloudOS-Kernel/include/trace/events/kvm.h

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 22:07:57 +08:00
/* SPDX-License-Identifier: GPL-2.0 */
#if !defined(_TRACE_KVM_MAIN_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_KVM_MAIN_H
#include <linux/tracepoint.h>
#undef TRACE_SYSTEM
#define TRACE_SYSTEM kvm
#define ERSN(x) { KVM_EXIT_##x, "KVM_EXIT_" #x }
#define kvm_trace_exit_reason \
ERSN(UNKNOWN), ERSN(EXCEPTION), ERSN(IO), ERSN(HYPERCALL), \
ERSN(DEBUG), ERSN(HLT), ERSN(MMIO), ERSN(IRQ_WINDOW_OPEN), \
ERSN(SHUTDOWN), ERSN(FAIL_ENTRY), ERSN(INTR), ERSN(SET_TPR), \
ERSN(TPR_ACCESS), ERSN(S390_SIEIC), ERSN(S390_RESET), ERSN(DCR),\
ERSN(NMI), ERSN(INTERNAL_ERROR), ERSN(OSI), ERSN(PAPR_HCALL), \
ERSN(S390_UCONTROL), ERSN(WATCHDOG), ERSN(S390_TSCH), ERSN(EPR),\
ERSN(SYSTEM_EVENT), ERSN(S390_STSI), ERSN(IOAPIC_EOI), \
ERSN(HYPERV)
TRACE_EVENT(kvm_userspace_exit,
TP_PROTO(__u32 reason, int errno),
TP_ARGS(reason, errno),
TP_STRUCT__entry(
__field( __u32, reason )
__field( int, errno )
),
TP_fast_assign(
__entry->reason = reason;
__entry->errno = errno;
),
TP_printk("reason %s (%d)",
__entry->errno < 0 ?
(__entry->errno == -EINTR ? "restart" : "error") :
__print_symbolic(__entry->reason, kvm_trace_exit_reason),
__entry->errno < 0 ? -__entry->errno : __entry->reason)
);
kvm: add halt_poll_ns module parameter This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-05 01:20:58 +08:00
TRACE_EVENT(kvm_vcpu_wakeup,
KVM: halt_polling: provide a way to qualify wakeups during poll Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> [Rename config symbol. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-13 18:16:35 +08:00
TP_PROTO(__u64 ns, bool waited, bool valid),
TP_ARGS(ns, waited, valid),
kvm: add halt_poll_ns module parameter This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-05 01:20:58 +08:00
TP_STRUCT__entry(
__field( __u64, ns )
__field( bool, waited )
KVM: halt_polling: provide a way to qualify wakeups during poll Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> [Rename config symbol. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-13 18:16:35 +08:00
__field( bool, valid )
kvm: add halt_poll_ns module parameter This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-05 01:20:58 +08:00
),
TP_fast_assign(
__entry->ns = ns;
__entry->waited = waited;
KVM: halt_polling: provide a way to qualify wakeups during poll Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> [Rename config symbol. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-13 18:16:35 +08:00
__entry->valid = valid;
kvm: add halt_poll_ns module parameter This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-05 01:20:58 +08:00
),
KVM: halt_polling: provide a way to qualify wakeups during poll Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> [Rename config symbol. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-13 18:16:35 +08:00
TP_printk("%s time %lld ns, polling %s",
kvm: add halt_poll_ns module parameter This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-05 01:20:58 +08:00
__entry->waited ? "wait" : "poll",
KVM: halt_polling: provide a way to qualify wakeups during poll Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> [Rename config symbol. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-13 18:16:35 +08:00
__entry->ns,
__entry->valid ? "valid" : "invalid")
kvm: add halt_poll_ns module parameter This patch introduces a new module parameter for the KVM module; when it is present, KVM attempts a bit of polling on every HLT before scheduling itself out via kvm_vcpu_block. This parameter helps a lot for latency-bound workloads---in particular I tested it with O_DSYNC writes with a battery-backed disk in the host. In this case, writes are fast (because the data doesn't have to go all the way to the platters) but they cannot be merged by either the host or the guest. KVM's performance here is usually around 30% of bare metal, or 50% if you use cache=directsync or cache=writethrough (these parameters avoid that the guest sends pointless flush requests, and at the same time they are not slow because of the battery-backed cache). The bad performance happens because on every halt the host CPU decides to halt itself too. When the interrupt comes, the vCPU thread is then migrated to a new physical CPU, and in general the latency is horrible because the vCPU thread has to be scheduled back in. With this patch performance reaches 60-65% of bare metal and, more important, 99% of what you get if you use idle=poll in the guest. This means that the tunable gets rid of this particular bottleneck, and more work can be done to improve performance in the kernel or QEMU. Of course there is some price to pay; every time an otherwise idle vCPUs is interrupted by an interrupt, it will poll unnecessarily and thus impose a little load on the host. The above results were obtained with a mostly random value of the parameter (500000), and the load was around 1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU. The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll, that can be used to tune the parameter. It counts how many HLT instructions received an interrupt during the polling period; each successful poll avoids that Linux schedules the VCPU thread out and back in, and may also avoid a likely trip to C1 and back for the physical CPU. While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second. Of these halts, almost all are failed polls. During the benchmark, instead, basically all halts end within the polling period, except a more or less constant stream of 50 per second coming from vCPUs that are not running the benchmark. The wasted time is thus very low. Things may be slightly different for Windows VMs, which have a ~10 ms timer tick. The effect is also visible on Marcelo's recently-introduced latency test for the TSC deadline timer. Though of course a non-RT kernel has awful latency bounds, the latency of the timer is around 8000-10000 clock cycles compared to 20000-120000 without setting halt_poll_ns. For the TSC deadline timer, thus, the effect is both a smaller average latency and a smaller variance. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-05 01:20:58 +08:00
);
#if defined(CONFIG_HAVE_KVM_IRQFD)
TRACE_EVENT(kvm_set_irq,
TP_PROTO(unsigned int gsi, int level, int irq_source_id),
TP_ARGS(gsi, level, irq_source_id),
TP_STRUCT__entry(
__field( unsigned int, gsi )
__field( int, level )
__field( int, irq_source_id )
),
TP_fast_assign(
__entry->gsi = gsi;
__entry->level = level;
__entry->irq_source_id = irq_source_id;
),
TP_printk("gsi %u level %d source %d",
__entry->gsi, __entry->level, __entry->irq_source_id)
);
#endif /* defined(CONFIG_HAVE_KVM_IRQFD) */
#if defined(__KVM_HAVE_IOAPIC)
#define kvm_deliver_mode \
{0x0, "Fixed"}, \
{0x1, "LowPrio"}, \
{0x2, "SMI"}, \
{0x3, "Res3"}, \
{0x4, "NMI"}, \
{0x5, "INIT"}, \
{0x6, "SIPI"}, \
{0x7, "ExtINT"}
TRACE_EVENT(kvm_ioapic_set_irq,
TP_PROTO(__u64 e, int pin, bool coalesced),
TP_ARGS(e, pin, coalesced),
TP_STRUCT__entry(
__field( __u64, e )
__field( int, pin )
__field( bool, coalesced )
),
TP_fast_assign(
__entry->e = e;
__entry->pin = pin;
__entry->coalesced = coalesced;
),
TP_printk("pin %u dst %x vec %u (%s|%s|%s%s)%s",
__entry->pin, (u8)(__entry->e >> 56), (u8)__entry->e,
__print_symbolic((__entry->e >> 8 & 0x7), kvm_deliver_mode),
(__entry->e & (1<<11)) ? "logical" : "physical",
(__entry->e & (1<<15)) ? "level" : "edge",
(__entry->e & (1<<16)) ? "|masked" : "",
__entry->coalesced ? " (coalesced)" : "")
);
TRACE_EVENT(kvm_ioapic_delayed_eoi_inj,
TP_PROTO(__u64 e),
TP_ARGS(e),
TP_STRUCT__entry(
__field( __u64, e )
),
TP_fast_assign(
__entry->e = e;
),
TP_printk("dst %x vec %u (%s|%s|%s%s)",
(u8)(__entry->e >> 56), (u8)__entry->e,
__print_symbolic((__entry->e >> 8 & 0x7), kvm_deliver_mode),
(__entry->e & (1<<11)) ? "logical" : "physical",
(__entry->e & (1<<15)) ? "level" : "edge",
(__entry->e & (1<<16)) ? "|masked" : "")
);
TRACE_EVENT(kvm_msi_set_irq,
TP_PROTO(__u64 address, __u64 data),
TP_ARGS(address, data),
TP_STRUCT__entry(
__field( __u64, address )
__field( __u64, data )
),
TP_fast_assign(
__entry->address = address;
__entry->data = data;
),
TP_printk("dst %llx vec %u (%s|%s|%s%s)",
(u8)(__entry->address >> 12) | ((__entry->address >> 32) & 0xffffff00),
(u8)__entry->data,
__print_symbolic((__entry->data >> 8 & 0x7), kvm_deliver_mode),
(__entry->address & (1<<2)) ? "logical" : "physical",
(__entry->data & (1<<15)) ? "level" : "edge",
(__entry->address & (1<<3)) ? "|rh" : "")
);
#define kvm_irqchips \
{KVM_IRQCHIP_PIC_MASTER, "PIC master"}, \
{KVM_IRQCHIP_PIC_SLAVE, "PIC slave"}, \
{KVM_IRQCHIP_IOAPIC, "IOAPIC"}
#endif /* defined(__KVM_HAVE_IOAPIC) */
#if defined(CONFIG_HAVE_KVM_IRQFD)
#ifdef kvm_irqchips
#define kvm_ack_irq_string "irqchip %s pin %u"
#define kvm_ack_irq_parm __print_symbolic(__entry->irqchip, kvm_irqchips), __entry->pin
#else
#define kvm_ack_irq_string "irqchip %d pin %u"
#define kvm_ack_irq_parm __entry->irqchip, __entry->pin
#endif
TRACE_EVENT(kvm_ack_irq,
TP_PROTO(unsigned int irqchip, unsigned int pin),
TP_ARGS(irqchip, pin),
TP_STRUCT__entry(
__field( unsigned int, irqchip )
__field( unsigned int, pin )
),
TP_fast_assign(
__entry->irqchip = irqchip;
__entry->pin = pin;
),
TP_printk(kvm_ack_irq_string, kvm_ack_irq_parm)
);
#endif /* defined(CONFIG_HAVE_KVM_IRQFD) */
#define KVM_TRACE_MMIO_READ_UNSATISFIED 0
#define KVM_TRACE_MMIO_READ 1
#define KVM_TRACE_MMIO_WRITE 2
#define kvm_trace_symbol_mmio \
{ KVM_TRACE_MMIO_READ_UNSATISFIED, "unsatisfied-read" }, \
{ KVM_TRACE_MMIO_READ, "read" }, \
{ KVM_TRACE_MMIO_WRITE, "write" }
TRACE_EVENT(kvm_mmio,
KVM: Fix stack-out-of-bounds read in write_mmio Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-15 09:40:50 +08:00
TP_PROTO(int type, int len, u64 gpa, void *val),
TP_ARGS(type, len, gpa, val),
TP_STRUCT__entry(
__field( u32, type )
__field( u32, len )
__field( u64, gpa )
__field( u64, val )
),
TP_fast_assign(
__entry->type = type;
__entry->len = len;
__entry->gpa = gpa;
KVM: Fix stack-out-of-bounds read in write_mmio Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-15 09:40:50 +08:00
__entry->val = 0;
if (val)
memcpy(&__entry->val, val,
min_t(u32, sizeof(__entry->val), len));
),
TP_printk("mmio %s len %u gpa 0x%llx val 0x%llx",
__print_symbolic(__entry->type, kvm_trace_symbol_mmio),
__entry->len, __entry->gpa, __entry->val)
);
#define kvm_fpu_load_symbol \
{0, "unload"}, \
{1, "load"}
TRACE_EVENT(kvm_fpu,
TP_PROTO(int load),
TP_ARGS(load),
TP_STRUCT__entry(
__field( u32, load )
),
TP_fast_assign(
__entry->load = load;
),
TP_printk("%s", __print_symbolic(__entry->load, kvm_fpu_load_symbol))
);
TRACE_EVENT(kvm_age_page,
TP_PROTO(ulong gfn, int level, struct kvm_memory_slot *slot, int ref),
TP_ARGS(gfn, level, slot, ref),
TP_STRUCT__entry(
__field( u64, hva )
__field( u64, gfn )
__field( u8, level )
__field( u8, referenced )
),
TP_fast_assign(
__entry->gfn = gfn;
__entry->level = level;
__entry->hva = ((gfn - slot->base_gfn) <<
PAGE_SHIFT) + slot->userspace_addr;
__entry->referenced = ref;
),
TP_printk("hva %llx gfn %llx level %u %s",
__entry->hva, __entry->gfn, __entry->level,
__entry->referenced ? "YOUNG" : "OLD")
);
#ifdef CONFIG_KVM_ASYNC_PF
DECLARE_EVENT_CLASS(kvm_async_get_page_class,
TP_PROTO(u64 gva, u64 gfn),
TP_ARGS(gva, gfn),
TP_STRUCT__entry(
__field(__u64, gva)
__field(u64, gfn)
),
TP_fast_assign(
__entry->gva = gva;
__entry->gfn = gfn;
),
TP_printk("gva = %#llx, gfn = %#llx", __entry->gva, __entry->gfn)
);
DEFINE_EVENT(kvm_async_get_page_class, kvm_try_async_get_page,
TP_PROTO(u64 gva, u64 gfn),
TP_ARGS(gva, gfn)
);
DEFINE_EVENT(kvm_async_get_page_class, kvm_async_pf_doublefault,
TP_PROTO(u64 gva, u64 gfn),
TP_ARGS(gva, gfn)
);
DECLARE_EVENT_CLASS(kvm_async_pf_nopresent_ready,
TP_PROTO(u64 token, u64 gva),
TP_ARGS(token, gva),
TP_STRUCT__entry(
__field(__u64, token)
__field(__u64, gva)
),
TP_fast_assign(
__entry->token = token;
__entry->gva = gva;
),
TP_printk("token %#llx gva %#llx", __entry->token, __entry->gva)
);
DEFINE_EVENT(kvm_async_pf_nopresent_ready, kvm_async_pf_not_present,
TP_PROTO(u64 token, u64 gva),
TP_ARGS(token, gva)
);
DEFINE_EVENT(kvm_async_pf_nopresent_ready, kvm_async_pf_ready,
TP_PROTO(u64 token, u64 gva),
TP_ARGS(token, gva)
);
TRACE_EVENT(
kvm_async_pf_completed,
TP_PROTO(unsigned long address, u64 gva),
TP_ARGS(address, gva),
TP_STRUCT__entry(
__field(unsigned long, address)
__field(u64, gva)
),
TP_fast_assign(
__entry->address = address;
__entry->gva = gva;
),
TP_printk("gva %#llx address %#lx", __entry->gva,
__entry->address)
);
#endif
TRACE_EVENT(kvm_halt_poll_ns,
TP_PROTO(bool grow, unsigned int vcpu_id, unsigned int new,
unsigned int old),
TP_ARGS(grow, vcpu_id, new, old),
TP_STRUCT__entry(
__field(bool, grow)
__field(unsigned int, vcpu_id)
__field(unsigned int, new)
__field(unsigned int, old)
),
TP_fast_assign(
__entry->grow = grow;
__entry->vcpu_id = vcpu_id;
__entry->new = new;
__entry->old = old;
),
TP_printk("vcpu %u: halt_poll_ns %u (%s %u)",
__entry->vcpu_id,
__entry->new,
__entry->grow ? "grow" : "shrink",
__entry->old)
);
#define trace_kvm_halt_poll_ns_grow(vcpu_id, new, old) \
trace_kvm_halt_poll_ns(true, vcpu_id, new, old)
#define trace_kvm_halt_poll_ns_shrink(vcpu_id, new, old) \
trace_kvm_halt_poll_ns(false, vcpu_id, new, old)
#endif /* _TRACE_KVM_MAIN_H */
/* This part must be outside protection */
#include <trace/define_trace.h>