a9a1790247
Jin Yao reported the issue (and posted first versions of this change)
with groups being defined over events with different cpu mask.
This causes assert aborts in get_group_fd, like:
# perf stat -M "C2_Pkg_Residency" -a -- sleep 1
perf: util/evsel.c:1464: get_group_fd: Assertion `!(fd == -1)' failed.
Aborted
All the events in the group have to be defined over the same cpus so the
group_fd can be found for every leader/member pair.
Adding check to ensure this condition is met and removing the group
(with warning) if we detect mixed cpus, like:
$ sudo perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}'
WARNING: event cpu maps do not match, disabling group:
anon group { power/energy-cores/, cycles }
anon group { instructions, power/energy-cores/ }
Ian asked also for cpu maps details, it's displayed in verbose mode:
$ sudo perf stat -e '{cycles,power/energy-cores/}' -v
WARNING: group events cpu maps do not match, disabling group:
anon group { power/energy-cores/, cycles }
power/energy-cores/: 0
cycles: 0-7
anon group { instructions, power/energy-cores/ }
instructions: 0-7
power/energy-cores/: 0
Committer testing:
[root@seventh ~]# perf stat -e '{power/energy-cores/,cycles},{instructions,power/energy-cores/}'
WARNING: grouped events cpus do not match, disabling group:
anon group { power/energy-cores/, cycles }
anon group { instructions, power/energy-cores/ }
^C
Performance counter stats for 'system wide':
12.62 Joules power/energy-cores/
106,920,637 cycles
80,228,899 instructions # 0.75 insn per cycle
12.62 Joules power/energy-cores/
14.514476987 seconds time elapsed
[root@seventh ~]#
But if we put compatible events in each group it works:
[root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' -a sleep 2
Performance counter stats for 'system wide':
1.95 Joules power/energy-cores/
0.92 Joules power/energy-ram/
29,305,715 instructions # 1.03 insn per cycle
28,423,338 cycles
2.001438142 seconds time elapsed
[root@seventh ~]#
This needs improvement tho:
[root@seventh ~]# perf stat -e '{power/energy-cores/,power/energy-ram/},{instructions,cycles}' sleep 2
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (power/energy-cores/).
/bin/dmesg | grep -i perf may provide additional information.
[root@seventh ~]#
We need to emit a better message, one stating that the power/ events
can't be used for a specific workload, instead it is per-cpu or system
wide.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.