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authorLai Jiangshan <laijs@cn.fujitsu.com>2010-06-03 14:26:24 +0400
committerSteven Rostedt <rostedt@goodmis.org>2010-07-21 06:05:34 +0400
commitbc289ae98b75d93228d24f521ef02a076e506e94 (patch)
tree50d151d0fbde1b106932c0f80a2639839d261ca3 /include/linux/ftrace_event.h
parent985023dee6e212493831431ba2e3ce8918f001b2 (diff)
downloadlinux-bc289ae98b75d93228d24f521ef02a076e506e94.tar.xz
tracing: Reduce latency and remove percpu trace_seq
__print_flags() and __print_symbolic() use percpu trace_seq: 1) Its memory is allocated at compile time, it wastes memory if we don't use tracing. 2) It is percpu data and it wastes more memory for multi-cpus system. 3) It disables preemption when it executes its core routine "trace_seq_printf(s, "%s: ", #call);" and introduces latency. So we move this trace_seq to struct trace_iterator. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4C078350.7090106@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ftrace_event.h')
-rw-r--r--include/linux/ftrace_event.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 2b7b1395b4d5..02b8b24f8f51 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -11,8 +11,6 @@ struct trace_array;
struct tracer;
struct dentry;
-DECLARE_PER_CPU(struct trace_seq, ftrace_event_seq);
-
struct trace_print_flags {
unsigned long mask;
const char *name;
@@ -58,6 +56,9 @@ struct trace_iterator {
struct ring_buffer_iter *buffer_iter[NR_CPUS];
unsigned long iter_flags;
+ /* trace_seq for __print_flags() and __print_symbolic() etc. */
+ struct trace_seq tmp_seq;
+
/* The below is zeroed out in pipe_read */
struct trace_seq seq;
struct trace_entry *ent;