Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: [PATCH V4 3/3] perf tool: Add sort key symoff for perf diff | Date | Thu, 20 Nov 2014 15:18:44 +0900 |
| |
On Tue, 18 Nov 2014 18:13:19 -0300, Arnaldo Carvalho de Melo wrote: > Em Tue, Nov 18, 2014 at 11:38:20AM -0500, kan.liang@intel.com escreveu: >> From: Kan Liang <kan.liang@intel.com> >> >> Sometime, especially debugging scaling issue, the function level diff >> may be high granularity. The user may want to do deeper diff analysis >> for some cache or lock issue. The "symoff" key can let the user sort >> differential profile by ips. This feature should only work when the >> perf.data comes from same binary. > > So, to avoid having people scratching heads, and since we have the > build-id for both perf.data files, hence for both binaries being > compared, can we check the build ids and either refuse to do the diff or > print a big warning about different binaries being compared?
Why do you think so? I think it's fine to use symoff for different binaries for same reason as the symbol sort key. Even if some functions were changed, other DSOs and/or functions still have same offset and thus have meaningful diff result IMHO.
Thanks, Namhyung
| |