• Frederic Weisbecker's avatar
    perf events, x86/stacktrace: Fix performance/softlockup by providing a special... · 06d65bda
    Frederic Weisbecker authored
    perf events, x86/stacktrace: Fix performance/softlockup by providing a special frame pointer-only stack walker
    
    It's just wasteful for stacktrace users like perf to walk
    through every entries on the stack whereas these only accept
    reliable ones, ie: that the frame pointer validates.
    
    Since perf requires pure reliable stacktraces, it needs a stack
    walker based on frame pointers-only to optimize the stacktrace
    processing.
    
    This might solve some near-lockup scenarios that can be triggered
    by call-graph tracing timer events.
    Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Paul Mackerras <paulus@samba.org>
    LKML-Reference: <1261024834-5336-2-git-send-regression-fweisbec@gmail.com>
    [ v2: fix for modular builds and small detail tidyup ]
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    06d65bda
perf_event.c 56.5 KB