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authorPaul Mackerras <paulus@samba.org>2009-05-14 21:48:08 +1000
committerIngo Molnar <mingo@elte.hu>2009-05-15 16:38:56 +0200
commit9d23a90a67261e73b2fcac04d8ca963c6b496afb (patch)
tree81d453624f1834380740d3065cf022fe3500aad6 /kernel
parentef923214a4816c289e4af2d67a9ebb1a31e4ac61 (diff)
perf_counter: allow arch to supply event misc flags and instruction pointer
At present the values we put in overflow events for the misc flags indicating processor mode and the instruction pointer are obtained using the standard user_mode() and instruction_pointer() functions. Those functions tell you where the performance monitor interrupt was taken, which might not be exactly where the counter overflow occurred, for example because interrupts were disabled at the point where the overflow occurred, or because the processor had many instructions in flight and chose to complete some more instructions beyond the one that caused the counter overflow. Some architectures (e.g. powerpc) can supply more precise information about where the counter overflow occurred and the processor mode at that point. This introduces new functions, perf_misc_flags() and perf_instruction_pointer(), which arch code can override to provide more precise information if available. They have default implementations which are identical to the existing code. This also adds a new misc flag value, PERF_EVENT_MISC_HYPERVISOR, for the case where a counter overflow occurred in the hypervisor. We encode the processor mode in the 2 bits previously used to indicate user or kernel mode; the values for user and kernel mode are unchanged and hypervisor mode is indicated by both bits being set. [ Impact: generalize perfcounter core facilities ] Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <18956.1272.818511.561835@cargo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_counter.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 728a595399b..57840a94b16 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2042,11 +2042,10 @@ static void perf_counter_output(struct perf_counter *counter,
header.size = sizeof(header);
header.misc = PERF_EVENT_MISC_OVERFLOW;
- header.misc |= user_mode(regs) ?
- PERF_EVENT_MISC_USER : PERF_EVENT_MISC_KERNEL;
+ header.misc |= perf_misc_flags(regs);
if (record_type & PERF_RECORD_IP) {
- ip = instruction_pointer(regs);
+ ip = perf_instruction_pointer(regs);
header.type |= PERF_RECORD_IP;
header.size += sizeof(ip);
}