Messages in this thread Patch in this message |  | | | 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 |
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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@gmail.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
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