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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/exit.c
parent4a0897526bbc5c6ac0df80b16b8c60339e717ae2 (diff)
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/exit.c')
-rw-r--r--kernel/exit.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 85a83c83185..7b71f87f120 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -47,6 +47,7 @@
#include <linux/blkdev.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/tracehook.h>
+#include <trace/sched.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -149,7 +150,10 @@ static void __exit_signal(struct task_struct *tsk)
static void delayed_put_task_struct(struct rcu_head *rhp)
{
- put_task_struct(container_of(rhp, struct task_struct, rcu));
+ struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
+ trace_sched_process_free(tsk);
+ put_task_struct(tsk);
}
@@ -1074,6 +1078,8 @@ NORET_TYPE void do_exit(long code)
if (group_dead)
acct_process();
+ trace_sched_process_exit(tsk);
+
exit_sem(tsk);
exit_files(tsk);
exit_fs(tsk);
@@ -1675,6 +1681,8 @@ static long do_wait(enum pid_type type, struct pid *pid, int options,
struct task_struct *tsk;
int retval;
+ trace_sched_process_wait(pid);
+
add_wait_queue(&current->signal->wait_chldexit,&wait);
repeat:
/*