Users can pass options to tracepoints defined in the BPF script. For
example:
# perf record -e ./test.c/no-inherit/ bash
# dd if=/dev/zero of=/dev/null count=10000
# exit
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.022 MB perf.data (139 samples) ]
(no-inherit works, only the sys_read issued by bash are captured, at
least 10000 sys_read issued by dd are skipped.)
test.c:
#define SEC(NAME) __attribute__((section(NAME), used))
SEC("func=sys_read")
int bpf_func__sys_read(void *ctx)
{
return 1;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
no-inherit is applied to the kprobe event defined in test.c.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1456132275-98875-10-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Copying perf to old kernel system results:
# perf test bpf
37: Test BPF filter :
37.1: Test basic BPF filtering : FAILED!
37.2: Test BPF prologue generation : Skip
However, in case when kernel doesn't support a test case it should
return 'Skip', 'FAILED!' should be reserved for kernel tests for when
the kernel supports a feature that then fails to work as advertised.
This patch checks environment before real testcase.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1453715801-7732-7-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
There's a bug in LLVM that it can generate unneeded relocation
information. See [1] and [2]. Libbpf should check the target section of
a relocation symbol.
This patch adds a testcase which references a global variable (BPF
doesn't support global variables). Before fixing libbpf, the new test
case can be loaded into kernel, the global variable acts like the first
map. It is incorrect.
Result:
# ~/perf test BPF
37: Test BPF filter :
37.1: Test basic BPF filtering : Ok
37.2: Test BPF prologue generation : Ok
37.3: Test BPF relocation checker : FAILED!
# ~/perf test -v BPF
...
libbpf: loading object '[bpf_relocation_test]' from buffer
libbpf: section .strtab, size 126, link 0, flags 0, type=3
libbpf: section .text, size 0, link 0, flags 6, type=1
libbpf: section .data, size 0, link 0, flags 3, type=1
libbpf: section .bss, size 0, link 0, flags 3, type=8
libbpf: section func=sys_write, size 104, link 0, flags 6, type=1
libbpf: found program func=sys_write
libbpf: section .relfunc=sys_write, size 16, link 10, flags 0, type=9
libbpf: section maps, size 16, link 0, flags 3, type=1
libbpf: maps in [bpf_relocation_test]: 16 bytes
libbpf: section license, size 4, link 0, flags 3, type=1
libbpf: license of [bpf_relocation_test] is GPL
libbpf: section version, size 4, link 0, flags 3, type=1
libbpf: kernel version of [bpf_relocation_test] is 40400
libbpf: section .symtab, size 144, link 1, flags 0, type=2
libbpf: map 0 is "my_table"
libbpf: collecting relocating info for: 'func=sys_write'
libbpf: relocation: insn_idx=7
Success unexpectedly: libbpf error when dealing with relocation
test child finished with -1
---- end ----
Test BPF filter subtest 2: FAILED!
[1] https://llvm.org/bugs/show_bug.cgi?id=26243
[2] https://patchwork.ozlabs.org/patch/571385/
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1453715801-7732-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch prints each sub-tests results for BPF testcases.
Before:
# ./perf test BPF
37: Test BPF filter : Ok
After:
# ./perf test BPF
37: Test BPF filter :
37.1: Test basic BPF filtering : Ok
37.2: Test BPF prologue generation : Ok
When a failure happens:
# cat ~/.perfconfig
[llvm]
clang-path = "/bin/false"
# ./perf test BPF
37: Test BPF filter :
37.1: Test basic BPF filtering : Skip
37.2: Test BPF prologue generation : Skip
Suggested-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447749170-175898-5-git-send-email-wangnan0@huawei.com
[ Fixed up not to use .func in an anonymous union ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Some tests have sub-tests we want to run, so allow passing this.
Wang tried to avoid having to touch all tests, but then, having the
test.func in an anonymous union makes the build fail on older compilers,
like the one in RHEL6, where:
test a = {
.func = foo,
};
fails.
To fix it leave the func pointer in the main structure and pass the subtest
index to all tests, end result function is the same, but we have just one
function pointer, not two, with and without the subtest index as an argument.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-5genj0ficwdmelpoqlds0u4y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Two bugs in 'perf test BPF' are found when testing BPF prologue without
vmlinux:
# mv /lib/modules/4.3.0-rc4+/build/vmlinux{,.bak}
# ./perf test BPF
37: Test BPF filter :Failed to find the path for kernel: No such file or directory
Ok
Test BPF should fail in this case.
After this patch:
# ./perf test BPF
37: Test BPF filter :Failed to find the path for kernel: No such file or directory
FAILED!
# mv /lib/modules/4.3.0-rc4+/build/vmlinux{.bak,}
# ./perf test BPF
37: Test BPF filter : Ok
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447749170-175898-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch introduces a new BPF script to test the BPF prologue adding
routines. The new script probes at null_lseek, which is the function pointer
used when we try to lseek on '/dev/null'.
The null_lseek function is chosen because it is used by function pointers, so
we don't need to consider inlining and LTO.
By extracting file->f_mode, bpf-script-test-prologue.c should know whether the
file is writable or readonly. According to llseek_loop() and
bpf-script-test-prologue.c, one fourth of total lseeks should be collected.
Committer note:
Testing it:
# perf test -v BPF
<SNIP>
Kernel build dir is set to /lib/modules/4.3.0+/build
set env: KBUILD_DIR=/lib/modules/4.3.0+/build
unset env: KBUILD_OPTS
include option is set to -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h
set env: NR_CPUS=4
set env: LINUX_VERSION_CODE=0x40300
set env: CLANG_EXEC=/usr/libexec/icecc/bin/clang
set env: CLANG_OPTIONS=-xc
set env: KERNEL_INC_OPTIONS= -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h
set env: WORKING_DIR=/lib/modules/4.3.0+/build
set env: CLANG_SOURCE=-
llvm compiling command template: echo '/*
* bpf-script-test-prologue.c
* Test BPF prologue
*/
#ifndef LINUX_VERSION_CODE
# error Need LINUX_VERSION_CODE
# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
#endif
#define SEC(NAME) __attribute__((section(NAME), used))
#include <uapi/linux/fs.h>
#define FMODE_READ 0x1
#define FMODE_WRITE 0x2
static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
(void *) 6;
SEC("func=null_lseek file->f_mode offset orig")
int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode,
unsigned long offset, unsigned long orig)
{
if (err)
return 0;
if (f_mode & FMODE_WRITE)
return 0;
if (offset & 1)
return 0;
if (orig == SEEK_CUR)
return 0;
return 1;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o -
libbpf: loading object '[bpf_prologue_test]' from buffer
libbpf: section .strtab, size 135, link 0, flags 0, type=3
libbpf: section .text, size 0, link 0, flags 6, type=1
libbpf: section .data, size 0, link 0, flags 3, type=1
libbpf: section .bss, size 0, link 0, flags 3, type=8
libbpf: section func=null_lseek file->f_mode offset orig, size 112, link 0, flags 6, type=1
libbpf: found program func=null_lseek file->f_mode offset orig
libbpf: section license, size 4, link 0, flags 3, type=1
libbpf: license of [bpf_prologue_test] is GPL
libbpf: section version, size 4, link 0, flags 3, type=1
libbpf: kernel version of [bpf_prologue_test] is 40300
libbpf: section .symtab, size 168, link 1, flags 0, type=2
bpf: config program 'func=null_lseek file->f_mode offset orig'
symbol:null_lseek file:(null) line:0 offset:0 return:0 lazy:(null)
parsing arg: file->f_mode into file, f_mode(1)
parsing arg: offset into offset
parsing arg: orig into orig
bpf: config 'func=null_lseek file->f_mode offset orig' is ok
Looking at the vmlinux_path (7 entries long)
Using /lib/modules/4.3.0+/build/vmlinux for symbols
Open Debuginfo file: /lib/modules/4.3.0+/build/vmlinux
Try to find probe point from debuginfo.
Matched function: null_lseek
Probe point found: null_lseek+0
Searching 'file' variable in context.
Converting variable file into trace event.
converting f_mode in file
f_mode type is unsigned int.
Searching 'offset' variable in context.
Converting variable offset into trace event.
offset type is long long int.
Searching 'orig' variable in context.
Converting variable orig into trace event.
orig type is int.
Found 1 probe_trace_events.
Opening /sys/kernel/debug/tracing//kprobe_events write=1
Writing event: p:perf_bpf_probe/func _text+4840528 f_mode=+68(%di):u32 offset=%si:s64 orig=%dx:s32
libbpf: don't need create maps for [bpf_prologue_test]
prologue: pass validation
prologue: slow path
prologue: fetch arg 0, base reg is %di
prologue: arg 0: offset 68
prologue: fetch arg 1, base reg is %si
prologue: fetch arg 2, base reg is %dx
add bpf event perf_bpf_probe:func and attach bpf program 3
adding perf_bpf_probe:func
adding perf_bpf_probe:func to 0x51672c0
mmap size 1052672B
Opening /sys/kernel/debug/tracing//kprobe_events write=1
Opening /sys/kernel/debug/tracing//uprobe_events write=1
Parsing probe_events: p:perf_bpf_probe/func _text+4840528 f_mode=+68(%di):u32 offset=%si:s64 orig=%dx:s32
Group:perf_bpf_probe Event:func probe:p
Writing event: -:perf_bpf_probe/func
test child finished with 0
---- end ----
Test BPF filter: Ok
#
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447675815-166222-13-git-send-email-wangnan0@huawei.com
[ Added tools/perf/tests/llvm-src-prologue.c to .gitignore ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
$ rpm -q glibc
glibc-2.12-1.166.el6_7.1.x86_64
<SNIP>
CC /tmp/build/perf/tests/llvm.o
cc1: warnings being treated as errors
tests/llvm.c: In function ‘test_llvm__fetch_bpf_obj’:
tests/llvm.c:53: error: declaration of ‘index’ shadows a global declaration
/usr/include/string.h:489: error: shadowed declaration is here
<SNIP>
CC /tmp/build/perf/tests/bpf.o
cc1: warnings being treated as errors
tests/bpf.c: In function ‘__test__bpf’:
tests/bpf.c:149: error: declaration of ‘index’ shadows a global declaration
/usr/include/string.h:489: error: shadowed declaration is here
<SNIP>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: pi3orama@163.com
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Fixes: b31de018a6 ("perf test: Enhance the LLVM test: update basic BPF test program")
Fixes: ba1fae431e ("perf test: Add 'perf test BPF'")
Link: http://lkml.kernel.org/n/tip-akpo4r750oya2phxoh9e3447@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch adds BPF testcase for testing BPF event filtering.
By utilizing the result of 'perf test LLVM', this patch compiles the
eBPF sample program then test its ability. The BPF script in 'perf test
LLVM' lets only 50% samples generated by epoll_pwait() to be captured.
This patch runs that system call for 111 times, so the result should
contain 56 samples.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446817783-86722-8-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Wang Nan