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authorJason Yeh <jason.yeh@amd.com>2009-07-08 13:49:38 +0200
committerRobert Richter <robert.richter@amd.com>2009-07-20 16:33:53 +0200
commit4d4036e0e7299c6cbb2d2421b4b30b7a409ce61a (patch)
treec9003cd927ed878412e89a59db0138b6b701b629 /include/linux/oprofile.h
parent6e63ea4b0b14ff5fb8a3ca704fcda7d28b95f079 (diff)
downloadlinux-linaro-stable-4d4036e0e7299c6cbb2d2421b4b30b7a409ce61a.tar.gz
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 <jason.yeh@amd.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'include/linux/oprofile.h')
-rw-r--r--include/linux/oprofile.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/oprofile.h b/include/linux/oprofile.h
index d68d2ed94f15..5171639ecf0f 100644
--- a/include/linux/oprofile.h
+++ b/include/linux/oprofile.h
@@ -67,6 +67,9 @@ struct oprofile_operations {
/* Initiate a stack backtrace. Optional. */
void (*backtrace)(struct pt_regs * const regs, unsigned int depth);
+
+ /* Multiplex between different events. Optional. */
+ int (*switch_events)(void);
/* CPU identification string. */
char * cpu_type;
};