From 2667de81f3256c944b06abdf2c56c2f192fcb724 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Sep 2009 19:01:10 +0200 Subject: perf_counter: Allow for a wakeup watermark Currently we wake the mmap() consumer once every PAGE_SIZE of data and/or once event wakeup_events when specified. For high speed sampling this results in too many wakeups wrt. the buffer size, hence change this. We move the default wakeup limit to 1/4-th the buffer size, and provide for means to manually specify this limit. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 972f90d..6c1ef72 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -199,10 +199,14 @@ struct perf_counter_attr { inherit_stat : 1, /* per task counts */ enable_on_exec : 1, /* next exec enables */ task : 1, /* trace fork/exit */ + watermark : 1, /* wakeup_watermark */ - __reserved_1 : 50; + __reserved_1 : 49; - __u32 wakeup_events; /* wakeup every n events */ + union { + __u32 wakeup_events; /* wakeup every n events */ + __u32 wakeup_watermark; /* bytes before wakeup */ + }; __u32 __reserved_2; __u64 __reserved_3; @@ -521,6 +525,8 @@ struct perf_mmap_data { atomic_t wakeup; /* needs a wakeup */ atomic_t lost; /* nr records lost */ + long watermark; /* wakeup watermark */ + struct perf_counter_mmap_page *user_page; void *data_pages[0]; }; -- cgit v1.1