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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-02-11 02:25:00 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-02-18 01:40:20 +0100 |
| commit | 6eaaa5d57e76c454479833fc8594cd7c3b75c789 (patch) | |
| tree | c8f3c130004199bbbc8d141bbfb0f216539c0724 /kernel/trace/trace_sched_switch.c | |
| parent | ac07bcaa8259841905ead3f8cd60b1923ca6c0e5 (diff) | |
| download | linux-6eaaa5d57e76c454479833fc8594cd7c3b75c789.tar.bz2 | |
tracing/core: use appropriate waiting on trace_pipe
Impact: api and pipe waiting change
Currently, the waiting used in tracing_read_pipe() is done through a
100 msecs schedule_timeout() loop which periodically check if there
are traces on the buffer.
This can cause small latencies for programs which are reading the incoming
events.
This patch makes the reader waiting for the trace_wait waitqueue except
for few tracers such as the sched and functions tracers which might be
already hold the runqueue lock while waking up the reader.
This is performed through a new callback wait_pipe() on struct tracer.
If none is implemented on a specific tracer, the default waiting for
trace_wait queue is attached.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace_sched_switch.c')
| -rw-r--r-- | kernel/trace/trace_sched_switch.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 82fbb5a2df89..77132c2cf3d9 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -221,6 +221,7 @@ static struct tracer sched_switch_trace __read_mostly = .reset = sched_switch_trace_reset, .start = sched_switch_trace_start, .stop = sched_switch_trace_stop, + .wait_pipe = poll_wait_pipe, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_sched_switch, #endif |