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authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2008-07-18 12:16:17 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-14 10:30:52 +0200
commit0a16b6075843325dc402edf80c1662838b929aff (patch)
tree124e49d8c0196f3c6eb7aa09a7c4c3c3157fff7a /kernel/fork.c
parent4a0897526bbc5c6ac0df80b16b8c60339e717ae2 (diff)
downloadlinux-0a16b6075843325dc402edf80c1662838b929aff.tar.bz2
tracing, sched: LTTng instrumentation - scheduler
Instrument the scheduler activity (sched_switch, migration, wakeups, wait for a task, signal delivery) and process/thread creation/destruction (fork, exit, kthread stop). Actually, kthread creation is not instrumented in this patch because it is architecture dependent. It allows to connect tracers such as ftrace which detects scheduling latencies, good/bad scheduler decisions. Tools like LTTng can export this scheduler information along with instrumentation of the rest of the kernel activity to perform post-mortem analysis on the scheduler activity. About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. See the "Tracepoints" patch header for performance result detail. Changelog : - Change instrumentation location and parameter to match ftrace instrumentation, previously done with kernel markers. [ mingo@elte.hu: conflict resolutions ] Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: 'Peter Zijlstra' <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 30de644a40c4..cfaff92f61ff 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -58,6 +58,7 @@
#include <linux/tty.h>
#include <linux/proc_fs.h>
#include <linux/blkdev.h>
+#include <trace/sched.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -1364,6 +1365,8 @@ long do_fork(unsigned long clone_flags,
if (!IS_ERR(p)) {
struct completion vfork;
+ trace_sched_process_fork(current, p);
+
nr = task_pid_vnr(p);
if (clone_flags & CLONE_PARENT_SETTID)