perf tools: Back [vdso] DSO with real data

2012-09-11T15:08:30Z

Storing data for VDSO shared object, because we need it for the post unwind processing. The VDSO shared object is same for all process on a running system, so it makes no difference when we store it inside the tracer - perf. When [vdso] map memory is hit, we retrieve [vdso] DSO image and store it into temporary file. During the build-id processing phase, the [vdso] DSO image is stored in build-id db, and build-id reference is made inside perf.data. The build-id vdso file object is called '[vdso]'. We don't use temporary file name which gets removed when record is finished. During report phase the vdso build-id object is treated as any other build-id DSO object. Adding following API for vdso object: bool is_vdso_map(const char *filename) - returns true if the filename matches vdso map name struct dso *vdso__dso_findnew(struct list_head *head) - find/create proper vdso DSO object vdso__exit(void) - removes temporary VDSO image if there's any This change makes backtrace dwarf post unwind possible from [vdso] maps. Following output is current report of [vdso] sample dwarf backtrace: # Overhead Command Shared Object Symbol # ........ ....... ................. ............................. # 99.52% ex [vdso] [.] 0x00007fff3ace89af | --- 0x7fff3ace89af Following output is new report of [vdso] sample dwarf backtrace: # Overhead Command Shared Object Symbol # ........ ....... ................. ............................. # 99.52% ex [vdso] [.] 0x00000000000009af | --- 0x7fff3ace89af main __libc_start_main _start Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1347295819-23177-5-git-send-email-jolsa@redhat.com [ committer note: s/ALIGN/PERF_ALIGN/g to cope with the android build changes ] Signed-off-by: Arnaldo Carvalho de Melo

kernel/tools/perf/util/vdso.h, branch linux-3.11.y

perf tools: Back [vdso] DSO with real data