linux-stable.git/arch/powerpc/perf, branch linux-3.7.y

Revert "powerpc/perf: Use pmc_overflow() to detect rolled back events"

2012-10-17T23:36:11+00:00

This reverts commit 813312110bede27bffd082c25cd31730bd567beb.

This revert was requested by the author of the patch as it seems
to cause system hangs with some low frequency events

powerpc/perf: Sample only if SIAR-Valid bit is set in P7+

2012-09-27T02:51:05+00:00

powerpc/perf: Sample only if SIAR-Valid bit is set in P7+

On POWER7+ two new bits (mmcra[35] and mmcra[36]) indicate whether the
contents of SIAR and SDAR are valid.

For marked instructions on P7+, we must save the contents of SIAR and
SDAR registers only if these new bits are set.

This code/check for the SIAR-Valid bit is specific to P7+, so rather than
waste a CPU-feature bit use the PVR flag.

Note that Carl Love proposed a similar change for oprofile:

        https://lkml.org/lkml/2012/6/22/309

Signed-off-by: Sukadev Bhattiprolu 
Signed-off-by: Benjamin Herrenschmidt

Merge branch 'merge' into next

2012-09-06T23:48:59+00:00

Brings in various bug fixes from 3.6-rcX

powerpc: Rename 64-bit PVR constants to PVR_foo

2012-09-05T05:19:35+00:00

We have an old FIXME in reg.h which points out that we should standardise
on PVR_foo for our PVR #defines. Currently we use PVR_ on 32-bit and PV_
on 64-bit.

So do that rename and remove the FIXME.

Seeing as we're touching all but one usage of __is_processor(), rename it
to something less ugly and more indicative of what it does, which is
simply to check the PVR version.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Use pmc_overflow() to detect rolled back events

2012-08-24T10:26:10+00:00

For certain speculative events on Power7, 'perf stat' reports far higher
event count than 'perf record' for the same event.

As described in following commit, a performance monitor exception is raised
even when the the performance events are rolled back.

        commit 0837e3242c73566fc1c0196b4ec61779c25ffc93
        Author: Anton Blanchard 
        Date:   Wed Mar 9 14:38:42 2011 +1100

perf_event_interrupt() records an event only when an overflow occurs. But
this check for overflow is a simple 'if (val < 0)'.

Because the events are rolled back, this check for overflow fails and the
event is not recorded. perf_event_interrupt() later uses pmc_overflow() to
detect the overflow and resets the counters and the events are lost completely.

To properly detect the overflow of rolled back events, use pmc_overflow()
even when recording events.

To reproduce:
        $ cat strcpy.c
        #include 
        #include 
        main()
        {
                char buf[256];

                alarm(5);
                while(1)
                        strcpy(buf, "string1");
        }

        $ perf record -e r20014 ./strcpy
        $ perf report -n > report.1
        $ perf stat -e r20014 > report.2
        # Compare report.1 and report.2

Reported-by: Maynard Johnson 
Signed-off-by: Sukadev Bhattiprolu 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Use perf_instruction_pointer in callchains

2012-07-10T09:18:46+00:00

We use SIAR or regs->nip for the instruction pointer depending on
the PMU configuration, but we always use regs->nip in the callchain.

Use perf_instruction_pointer so the backtrace is consistent.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Always use pt_regs for userspace samples

2012-07-10T09:18:43+00:00

At the moment we always use the SIAR if the PMU supports continuous
sampling. Unfortunately the SIAR and the PMU exception are not
synchronised for non marked events so we can end up with callchains
that dont make sense.

The following patch checks the HV and PR bits for samples coming from
userspace and always uses pt_regs for them. Userspace will never have
interrupts off so there is no real advantage to using the SIAR for
non marked events in userspace.

I had experimented with a patch that did a similar thing for kernel
samples but we lost a significant amount of information. I was
unable to profile any of our early exception code for example.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Move code to select SIAR or pt_regs into perf_read_regs

2012-07-10T09:18:41+00:00

The logic to choose whether to use the SIAR or get the information
out of pt_regs is going to get more complicated, so do it once in
perf_read_regs.

We overload regs->result which is gross but we are already doing it
with regs->dsisr.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Create mmcra_sihv/mmcra_sipv helpers

2012-07-10T09:18:38+00:00

We want to access the MMCRA_SIHV and MMCRA_SIPR bits elsewhere so
create mmcra_sihv and mmcra_sipr which hide the differences between
the old and new layout of the bits.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt

perf: Pass last sampling period to perf_sample_data_init()

2012-05-09T13:23:12+00:00

We always need to pass the last sample period to
perf_sample_data_init(), otherwise the event distribution will be
wrong. Thus, modifiyng the function interface with the required period
as argument. So basically a pattern like this:

        perf_sample_data_init(&data, ~0ULL);
        data.period = event->hw.last_period;

will now be like that:

        perf_sample_data_init(&data, ~0ULL, event->hw.last_period);

Avoids unininitialized data.period and simplifies code.

Signed-off-by: Robert Richter 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1333390758-10893-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar