From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756596AbZCEBBB (ORCPT ); Wed, 4 Mar 2009 20:01:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750972AbZCEBAu (ORCPT ); Wed, 4 Mar 2009 20:00:50 -0500 Received: from ey-out-2122.google.com ([74.125.78.26]:18020 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754850AbZCEBAt (ORCPT ); Wed, 4 Mar 2009 20:00:49 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:from:date:subject:to:cc; b=flExjWihDDSA85OipO8RByho12qFd1ECTS2PlMwShd9PifyV011N1Av10B+3wfChzV Lq2cOjqv1HLhIbAtDUeG/lnUN/lytUE7LAnUSUlm46T2SaKKQQ69VkaAUgBsRQcweP8m 8f+xLZLMkyTTwP9WhPDwtphG+Kvsyl/bneOU0= Message-ID: <49af243d.06e9300a.53ad.ffff840c@mx.google.com> From: Frederic Weisbecker Date: Thu, 5 Mar 2009 01:49:22 +0100 Subject: [PATCH 2/2] tracing/function-graph-tracer: use the more lightweight local clock To: Ingo Molnar Cc: Steven Rostedt , Peter Zijlstra , linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Impact: decrease hangs risks with the graph tracer on slow systems Since the function graph tracer can spend too much time on timer interrupts, it's better now to use the more lightweight local clock. Anyway, the function graph traces are more reliable on a per cpu trace. Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/ftrace.c | 2 +- kernel/trace/trace_functions_graph.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 3925ec0..40960c2 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -436,7 +436,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) return; } - calltime = cpu_clock(raw_smp_processor_id()); + calltime = sched_clock(); if (ftrace_push_return_trace(old, calltime, self_addr, &trace.depth) == -EBUSY) { diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 2461732..c5038f4 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -112,7 +112,7 @@ unsigned long ftrace_return_to_handler(void) unsigned long ret; ftrace_pop_return_trace(&trace, &ret); - trace.rettime = cpu_clock(raw_smp_processor_id()); + trace.rettime = sched_clock(); ftrace_graph_return(&trace); if (unlikely(!ret)) { -- 1.6.1