linux-kernel - [PATCH 2/2] tracing/function-graph-tracer: use the more lightweight local clock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <49af243d.06e9300a.53ad.ffff840c@mx.google.com>
Date:	Thu, 5 Mar 2009 01:49:22 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] tracing/function-graph-tracer: use the more lightweight local clock

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 <fweisbec@...il.com>
---
 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


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/