Zhang, Yanmin 46be604b5b perf record: Enable counters only when kernel is execing subcommand ... 'perf record' starts counters before subcommand is execed, so the statistics is not precise because it includes data of some preparation steps. I fix it with the patch. In addition, change the condition to fork/exec subcommand. If there is a subcommand parameter, perf always fork/exec it. The usage example is: # perf record -f -a sleep 10 So this command could collect statistics for 10 seconds precisely. User still could stop it by CTRL+C. Without the new capability, user could only input CTRL+C to stop it without precise time clock. Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Avi Kivity <avi@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sheng Yang <sheng@linux.intel.com> Cc: oerg Roedel <joro@8bytes.org> Cc: Jes Sorensen <Jes.Sorensen@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: <zhiteng.huang@intel.com> Cc: Zachary Amsden <zamsden@redhat.com> LKML-Reference: <1268922965-14774-2-git-send-email-acme@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2010-03-18 16:21:11 +01:00
..
perf	perf record: Enable counters only when kernel is execing subcommand	2010-03-18 16:21:11 +01:00