Symbol versioning, as in glibc, results in symbols being defined as:
<real symbol>@[@]<version>
(Note that "@@" identifies a default symbol, if the symbol name is
repeated.)
perf is currently unable to deal with this, and is unable to create user
probes at such symbols:
--
$ nm /lib/powerpc64le-linux-gnu/libpthread.so.0 | grep pthread_create
0000000000008d30 t __pthread_create_2_1
0000000000008d30 T pthread_create@@GLIBC_2.17
$ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create
probe-definition(0): pthread_create
symbol:pthread_create file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
Open Debuginfo file: /usr/lib/debug/lib/powerpc64le-linux-gnu/libpthread-2.19.so
Try to find probe point from debuginfo.
Probe point 'pthread_create' not found.
Error: Failed to add events. Reason: No such file or directory (Code: -2)
--
One is not able to specify the fully versioned symbol, either, due to
syntactic conflicts with other uses of "@" by perf:
--
$ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create@@GLIBC_2.17
probe-definition(0): pthread_create@@GLIBC_2.17
Semantic error :SRC@SRC is not allowed.
0 arguments
Error: Command Parse Error. Reason: Invalid argument (Code: -22)
--
This patch ignores versioning for default symbols, thus allowing probes to be
created for these symbols:
--
$ /usr/bin/sudo ./perf probe -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create
Added new event:
probe_libpthread:pthread_create (on pthread_create in /lib/powerpc64le-linux-gnu/libpthread-2.19.so)
You can now use it in all perf tools, such as:
perf record -e probe_libpthread:pthread_create -aR sleep 1
$ /usr/bin/sudo ./perf record -e probe_libpthread:pthread_create -aR ./test 2
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.052 MB perf.data (2 samples) ]
$ /usr/bin/sudo ./perf script
test 2915 [000] 19124.260729: probe_libpthread:pthread_create: (3fff99248d38)
test 2916 [000] 19124.260962: probe_libpthread:pthread_create: (3fff99248d38)
$ /usr/bin/sudo ./perf probe --del=probe_libpthread:pthread_create
Removed event: probe_libpthread:pthread_create
--
Committer note:
Change the variable storing the result of strlen() to 'int', to fix the build
on debian:experimental-x-mipsel, fedora:24-x-ARC-uClibc, ubuntu:16.04-x-arm,
etc:
util/symbol.c: In function 'symbol__match_symbol_name':
util/symbol.c:422:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
if (len < versioning - name)
^
Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/c2b18d9c-17f8-9285-4868-f58b6359ccac@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
That is the case of _text on s390, and we have some functions that return an
address, using address zero to report problems, oops.
This would lead the symbol loading routines to not use "_text" as the reference
relocation symbol, or the first symbol for the kernel, but use instead
"_stext", that is at the same address on x86_64 and others, but not on s390:
[acme@localhost perf-4.11.0-rc6]$ head -15 /proc/kallsyms
0000000000000000 T _text
0000000000000418 t iplstart
0000000000000800 T start
000000000000080a t .base
000000000000082e t .sk8x8
0000000000000834 t .gotr
0000000000000842 t .cmd
0000000000000846 t .parm
000000000000084a t .lowcase
0000000000010000 T startup
0000000000010010 T startup_kdump
0000000000010214 t startup_kdump_relocated
0000000000011000 T startup_continue
00000000000112a0 T _ehead
0000000000100000 T _stext
[acme@localhost perf-4.11.0-rc6]$
Which in turn would make 'perf test vmlinux' to fail because it wouldn't find
the symbols before "_stext" in kallsyms.
Fix it by using the return value only for errors and storing the
address, when the symbol is successfully found, in a provided pointer
arg.
Before this patch:
After:
[acme@localhost perf-4.11.0-rc6]$ tools/perf/perf test -v 1
1: vmlinux symtab matches kallsyms :
--- start ---
test child forked, pid 40693
Looking at the vmlinux_path (8 entries long)
Using /usr/lib/debug/lib/modules/3.10.0-654.el7.s390x/vmlinux for symbols
ERR : 0: _text not on kallsyms
ERR : 0x418: iplstart not on kallsyms
ERR : 0x800: start not on kallsyms
ERR : 0x80a: .base not on kallsyms
ERR : 0x82e: .sk8x8 not on kallsyms
ERR : 0x834: .gotr not on kallsyms
ERR : 0x842: .cmd not on kallsyms
ERR : 0x846: .parm not on kallsyms
ERR : 0x84a: .lowcase not on kallsyms
ERR : 0x10000: startup not on kallsyms
ERR : 0x10010: startup_kdump not on kallsyms
ERR : 0x10214: startup_kdump_relocated not on kallsyms
ERR : 0x11000: startup_continue not on kallsyms
ERR : 0x112a0: _ehead not on kallsyms
<SNIP warnings>
test child finished with -1
---- end ----
vmlinux symtab matches kallsyms: FAILED!
[acme@localhost perf-4.11.0-rc6]$
After:
[acme@localhost perf-4.11.0-rc6]$ tools/perf/perf test -v 1
1: vmlinux symtab matches kallsyms :
--- start ---
test child forked, pid 47160
<SNIP warnings>
test child finished with 0
---- end ----
vmlinux symtab matches kallsyms: Ok
[acme@localhost perf-4.11.0-rc6]$
Reported-by: Michael Petlan <mpetlan@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-9x9bwgd3btwdk1u51xie93fz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The util/event.h header needs PERF_ALIGN(), but wasn't including
linux/kernel.h, where it is defined, instead it was getting it by
luck by including map.h, which it doesn't need at all.
Fix it by including the right header.
Link: http://lkml.kernel.org/n/tip-nf3t9blzm5ncoxsczi8oy9mx@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
As it is going away from util.h, where it is not needed.
This is mostly for things like MAXPATHLEN, MAX() and MIN(), these later
two probably should go away in favor of its kernel sources replacements.
Link: http://lkml.kernel.org/n/tip-z1666f3fl3fqobxvjr5o2r39@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
'perf mem report' doesn't display the data source snoop indication correctly.
In the kernel API the definition is:
#define PERF_MEM_SNOOP_NONE 0x02 /* no snoop */
#define PERF_MEM_SNOOP_HIT 0x04 /* snoop hit */
#define PERF_MEM_SNOOP_MISS 0x08 /* snoop miss */
but the table used by the perf tools exchanged "Hit" and "Miss":
"None",
"Miss",
"Hit",
Fix the table in perf.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20170419174940.13641-1-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
