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authorIngo Molnar <mingo@elte.hu>2008-12-12 13:49:45 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-14 20:30:49 +0100
commit9b51f66dcb09ac5eb6bc68fc111d5c7a1e0131d6 (patch)
treef7b3482ae284c214119efe309e356fb84de126bb /kernel/exit.c
parentee06094f8279e1312fc0a31591320cc7b6f0ab1e (diff)
downloadop-kernel-dev-9b51f66dcb09ac5eb6bc68fc111d5c7a1e0131d6.zip
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perfcounters: implement "counter inheritance"
Impact: implement new performance feature Counter inheritance can be used to run performance counters in a workload, transparently - and pipe back the counter results to the parent counter. Inheritance for performance counters works the following way: when creating a counter it can be marked with the .inherit=1 flag. Such counters are then 'inherited' by all child tasks (be they fork()-ed or clone()-ed). These counters get inherited through exec() boundaries as well (except through setuid boundaries). The counter values get added back to the parent counter(s) when the child task(s) exit - much like stime/utime statistics are gathered. So inherited counters are ideal to gather summary statistics about an application's behavior via shell commands, without having to modify that application. The timec.c command utilizes counter inheritance: http://redhat.com/~mingo/perfcounters/timec.c Sample output: $ ./timec -e 1 -e 3 -e 5 ls -lR /usr/include/ >/dev/null Performance counter stats for 'ls': 163516953 instructions 2295 cache-misses 2855182 branch-misses Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 2d8be7e..d336c90 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1093,11 +1093,12 @@ NORET_TYPE void do_exit(long code)
mpol_put(tsk->mempolicy);
tsk->mempolicy = NULL;
#endif
-#ifdef CONFIG_FUTEX
/*
- * This must happen late, after the PID is not
- * hashed anymore:
+ * These must happen late, after the PID is not
+ * hashed anymore, but still at a point that may sleep:
*/
+ perf_counter_exit_task(tsk);
+#ifdef CONFIG_FUTEX
if (unlikely(!list_empty(&tsk->pi_state_list)))
exit_pi_state_list(tsk);
if (unlikely(current->pi_state_cache))
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