Messages in this thread Patch in this message | | | Subject | Re: [PATCH v4 0/2] perf, x86: handle overlapping counters | From | Peter Zijlstra <> | Date | Fri, 18 Nov 2011 16:10:17 +0100 |
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On Fri, 2011-11-18 at 12:35 +0100, Robert Richter wrote: > I know there is an ongoing discussion about the best algorithm to be > used for this problem. Posting this version with the latest updates > anyway... > > This patch set implements support for overlapping counters (patch #2). > For this the existing x86 event scheduler is reworked by introducing > helper functions (patch #1). > > Version 4 of the patch set fixes a bug in the event assignment. There was a > problem if the first event's weight (index 0) is not the minimum weight. In > this case the event was assigned twice leaving another event uninitialized > which caused a GP while accessing counter msrs. Fixes this by proper > initialzing the first event in perf_sched_init().
OK, I've queued these and tested them using something like:
Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel.c +++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel.c @@ -88,13 +88,19 @@ static struct extra_reg intel_nehalem_ex static struct event_constraint intel_westmere_event_constraints[] __read_mostly = { - FIXED_EVENT_CONSTRAINT(0x00c0, 0), /* INST_RETIRED.ANY */ - FIXED_EVENT_CONSTRAINT(0x003c, 1), /* CPU_CLK_UNHALTED.CORE */ +// FIXED_EVENT_CONSTRAINT(0x00c0, 0), /* INST_RETIRED.ANY */ +// FIXED_EVENT_CONSTRAINT(0x003c, 1), /* CPU_CLK_UNHALTED.CORE */ /* FIXED_EVENT_CONSTRAINT(0x013c, 2), CPU_CLK_UNHALTED.REF */ INTEL_EVENT_CONSTRAINT(0x51, 0x3), /* L1D */ INTEL_EVENT_CONSTRAINT(0x60, 0x1), /* OFFCORE_REQUESTS_OUTSTANDING */ INTEL_EVENT_CONSTRAINT(0x63, 0x3), /* CACHE_LOCK_CYCLES */ INTEL_EVENT_CONSTRAINT(0xb3, 0x1), /* SNOOPQ_REQUEST_OUTSTANDING */ + + EVENT_CONSTRAINT_OVERLAP(0x003c, 0x1|0x2, INTEL_ARCH_EVENT_MASK), + EVENT_CONSTRAINT_OVERLAP(0x00c0, 0x2|0x4, INTEL_ARCH_EVENT_MASK), + EVENT_CONSTRAINT_OVERLAP(0x4f2e, 0x4|0x8, INTEL_ARCH_EVENT_MASK), + EVENT_CONSTRAINT_OVERLAP(0x412e, 0x8|0x1, INTEL_ARCH_EVENT_MASK), + EVENT_CONSTRAINT_END }; To stress the thing, you can quite easily manage to hit that WARN_ON_ONCE() in there, but I haven't seen things explode yet.
> Robert Richter (2): > configs: updating misc-x86_64-erda to v3.0.8 > config: updating misc-x86_64-erda.config for ASUS M4A89GTD PRO > > configs/misc-x86_64-erda.config | 517 ++++++++++++++++++++++++++++----------- > 1 files changed, 379 insertions(+), 138 deletions(-)
You sure about that? :-)
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