From 4d4036e0e7299c6cbb2d2421b4b30b7a409ce61a Mon Sep 17 00:00:00 2001 From: Jason Yeh Date: Wed, 8 Jul 2009 13:49:38 +0200 Subject: oprofile: Implement performance counter multiplexing The number of hardware counters is limited. The multiplexing feature enables OProfile to gather more events than counters are provided by the hardware. This is realized by switching between events at an user specified time interval. A new file (/dev/oprofile/time_slice) is added for the user to specify the timer interval in ms. If the number of events to profile is higher than the number of hardware counters available, the patch will schedule a work queue that switches the event counter and re-writes the different sets of values into it. The switching mechanism needs to be implemented for each architecture to support multiplexing. This patch only implements AMD CPU support, but multiplexing can be easily extended for other models and architectures. There are follow-on patches that rework parts of this patch. Signed-off-by: Jason Yeh Signed-off-by: Robert Richter --- drivers/oprofile/oprofile_stats.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/oprofile/oprofile_stats.c') diff --git a/drivers/oprofile/oprofile_stats.c b/drivers/oprofile/oprofile_stats.c index 3c2270a8300c..77a57a6792f6 100644 --- a/drivers/oprofile/oprofile_stats.c +++ b/drivers/oprofile/oprofile_stats.c @@ -16,6 +16,9 @@ #include "cpu_buffer.h" struct oprofile_stat_struct oprofile_stats; +#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX +atomic_t multiplex_counter; +#endif void oprofile_reset_stats(void) { @@ -34,6 +37,9 @@ void oprofile_reset_stats(void) atomic_set(&oprofile_stats.sample_lost_no_mapping, 0); atomic_set(&oprofile_stats.event_lost_overflow, 0); atomic_set(&oprofile_stats.bt_lost_no_mapping, 0); +#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX + atomic_set(&multiplex_counter, 0); +#endif } @@ -76,4 +82,8 @@ void oprofile_create_stats_files(struct super_block *sb, struct dentry *root) &oprofile_stats.event_lost_overflow); oprofilefs_create_ro_atomic(sb, dir, "bt_lost_no_mapping", &oprofile_stats.bt_lost_no_mapping); +#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX + oprofilefs_create_ro_atomic(sb, dir, "multiplex_counter", + &multiplex_counter); +#endif } -- cgit v1.2.1