1. 14 Oct, 2009 2 commits
    • jolsa@redhat.com's avatar
      tracing: Support multiple pids in set_pid_ftrace file · 756d17ee
      jolsa@redhat.com authored
      Adding the possibility to set more than 1 pid in the set_pid_ftrace
      file, thus allowing to trace more than 1 independent processes.
      
      Usage:
      
       sh-4.0# echo 284 > ./set_ftrace_pid
       sh-4.0# cat ./set_ftrace_pid
       284
       sh-4.0# echo 1 >> ./set_ftrace_pid
       sh-4.0# echo 0 >> ./set_ftrace_pid
       sh-4.0# cat ./set_ftrace_pid
       swapper tasks
       1
       284
       sh-4.0# echo 4 > ./set_ftrace_pid
       sh-4.0# cat ./set_ftrace_pid
       4
       sh-4.0# echo > ./set_ftrace_pid
       sh-4.0# cat ./set_ftrace_pid
       no pid
       sh-4.0#
      Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <20091013203425.565454612@goodmis.org>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      756d17ee
    • Steven Rostedt's avatar
      function-graph/x86: Replace unbalanced ret with jmp · 194ec341
      Steven Rostedt authored
      The function graph tracer replaces the return address with a hook
      to trace the exit of the function call. This hook will finish by
      returning to the real location the function should return to.
      
      But the current implementation uses a ret to jump to the real
      return location. This causes a imbalance between calls and ret.
      That is the original function does a call, the ret goes to the
      handler and then the handler does a ret without a matching call.
      
      Although the function graph tracer itself still breaks the branch
      predictor by replacing the original ret, by using a second ret and
      causing an imbalance, it breaks the predictor even more.
      
      This patch replaces the ret with a jmp to keep the calls and ret
      balanced. I tested this on one box and it showed a 1.7% increase in
      performance. Another box only showed a small 0.3% increase. But no
      box that I tested this on showed a decrease in performance by
      making this change.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <20091013203425.042034383@goodmis.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      194ec341
  2. 13 Oct, 2009 5 commits
  3. 12 Oct, 2009 3 commits
  4. 09 Oct, 2009 1 commit
  5. 08 Oct, 2009 2 commits
  6. 07 Oct, 2009 3 commits
  7. 06 Oct, 2009 1 commit
  8. 05 Oct, 2009 2 commits
  9. 04 Oct, 2009 8 commits
  10. 03 Oct, 2009 6 commits
  11. 02 Oct, 2009 7 commits