perf/x86-ibs: Fix update of period

The last sw period was not correctly updated on overflow and thus led
to wrong distribution of events. We always need to properly initialize
data.period in struct perf_sample_data.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1333390758-10893-2-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index 8ff74d43904128af47eb043bba8bf9d4ca537fd9..c8f69bea66245ab0ae82c770c2b774b1eaf96ead 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -386,7 +386,21 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
        if (!(*buf++ & perf_ibs->valid_mask))
                return 0;
 
+       /*
+        * Emulate IbsOpCurCnt in MSRC001_1033 (IbsOpCtl), not
+        * supported in all cpus. As this triggered an interrupt, we
+        * set the current count to the max count.
+        */
+       config = ibs_data.regs[0];
+       if (perf_ibs == &perf_ibs_op && !(ibs_caps & IBS_CAPS_RDWROPCNT)) {
+               config &= ~IBS_OP_CUR_CNT;
+               config |= (config & IBS_OP_MAX_CNT) << 36;
+       }
+
+       perf_ibs_event_update(perf_ibs, event, config);
        perf_sample_data_init(&data, 0);
+       data.period = event->hw.last_period;
+
        if (event->attr.sample_type & PERF_SAMPLE_RAW) {
                ibs_data.caps = ibs_caps;
                size = 1;
@@ -405,19 +419,6 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 
        regs = *iregs; /* XXX: update ip from ibs sample */
 
-       /*
-        * Emulate IbsOpCurCnt in MSRC001_1033 (IbsOpCtl), not
-        * supported in all cpus. As this triggered an interrupt, we
-        * set the current count to the max count.
-        */
-       config = ibs_data.regs[0];
-       if (perf_ibs == &perf_ibs_op && !(ibs_caps & IBS_CAPS_RDWROPCNT)) {
-               config &= ~IBS_OP_CUR_CNT;
-               config |= (config & IBS_OP_MAX_CNT) << 36;
-       }
-
-       perf_ibs_event_update(perf_ibs, event, config);
-
        overflow = perf_ibs_set_period(perf_ibs, hwc, &config);
        reenable = !(overflow && perf_event_overflow(event, &data, &regs));
        config = (config >> 4) | (reenable ? perf_ibs->enable_mask : 0);