From 710944c4e1f7468dba1a0c4fa36b4cda5846f350 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Wed, 16 Mar 2011 19:05:58 -0400 Subject: trace-clock-remove-extra-barriers-on-x86 trace clock remove extra barriers on x86 Given that a tracer cannot realistically provide accuracy better than the inaccuracy between the traced action (e.g. an atomic operation) and the timestamp read, having barriers around the timestamp read is just overkill. This will speed up tracing. Signed-off-by: Mathieu Desnoyers --- arch/x86/kernel/trace-clock.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/trace-clock.c b/arch/x86/kernel/trace-clock.c index ec866aa9591..37cf125a940 100644 --- a/arch/x86/kernel/trace-clock.c +++ b/arch/x86/kernel/trace-clock.c @@ -69,9 +69,7 @@ notrace cycles_t trace_clock_async_tsc_read(void) cycles_t new_tsc, last_tsc; WARN_ON(!async_tsc_refcount || !async_tsc_enabled); - rdtsc_barrier(); new_tsc = get_cycles(); - rdtsc_barrier(); last_tsc = read_last_tsc(); do { if (new_tsc < last_tsc) -- cgit v1.2.3