Re: [PATCH 09/13] perf_events: disable PERF_SAMPLE_BRANCH_* when notsupported (v3)

[Stephane Eranian]

On Fri, Jan 27, 2012 at 8:15 AM, Anshuman Khandual
<khandual@xxxxxxxxxxxxxxxxxx> wrote:
> On Monday 09 January 2012 10:19 PM, Stephane Eranian wrote:
>> PERF_SAMPLE_BRANCH_* is disabled for:
>> - SW events (sw counters, tracepoints)
>> - HW breakpoints
>> - ALL but Intel X86 architecture
>> - AMD64 processors
>>
>> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
>> ---
>> Âarch/alpha/kernel/perf_event.c    |  Â4 ++++
>> Âarch/arm/kernel/perf_event.c     |  Â4 ++++
>> Âarch/mips/kernel/perf_event_mipsxx.c | Â Â4 ++++
>> Âarch/powerpc/kernel/perf_event.c   |  Â4 ++++
>> Âarch/sh/kernel/perf_event.c     Â|  Â4 ++++
>> Âarch/sparc/kernel/perf_event.c    |  Â4 ++++
>> Âarch/x86/kernel/cpu/perf_event_amd.c | Â Â3 +++
>> Âkernel/events/core.c         |  24 ++++++++++++++++++++++++
>> Âkernel/events/hw_breakpoint.c    Â|  Â6 ++++++
>> Â9 files changed, 57 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/alpha/kernel/perf_event.c b/arch/alpha/kernel/perf_event.c
>> index 8143cd7..0dae252 100644
>> --- a/arch/alpha/kernel/perf_event.c
>> +++ b/arch/alpha/kernel/perf_event.c
>> @@ -685,6 +685,10 @@ static int alpha_pmu_event_init(struct perf_event *event)
>> Â{
>> Â Â Â int err;
>>
>> + Â Â /* does not support taken branch sampling */
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â switch (event->attr.type) {
>> Â Â Â case PERF_TYPE_RAW:
>> Â Â Â case PERF_TYPE_HARDWARE:
>> diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
>> index 88b0941..42262ff 100644
>> --- a/arch/arm/kernel/perf_event.c
>> +++ b/arch/arm/kernel/perf_event.c
>> @@ -540,6 +540,10 @@ static int armpmu_event_init(struct perf_event *event)
>> Â Â Â int err = 0;
>> Â Â Â atomic_t *active_events = &armpmu->active_events;
>>
>> + Â Â /* does not support taken branch sampling */
>> + Â Â if (has_branch_smpl(event))
> I guess this would be 'has_branch_stack' instead of 'has_branch_smpl'.
> 'has_branch_smpl' has not been defined any where but getting called here.

Good catch. Will post a patch to fix that.

>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â if (armpmu->map_event(event) == -ENOENT)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
>> index 315fc0b..7070f8c 100644
>> --- a/arch/mips/kernel/perf_event_mipsxx.c
>> +++ b/arch/mips/kernel/perf_event_mipsxx.c
>> @@ -606,6 +606,10 @@ static int mipspmu_event_init(struct perf_event *event)
>> Â{
>> Â Â Â int err = 0;
>>
>> + Â Â /* does not support taken branch sampling */
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â switch (event->attr.type) {
>> Â Â Â case PERF_TYPE_RAW:
>> Â Â Â case PERF_TYPE_HARDWARE:
>> diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
>> index d614ab5..4e0b265 100644
>> --- a/arch/powerpc/kernel/perf_event.c
>> +++ b/arch/powerpc/kernel/perf_event.c
>> @@ -1078,6 +1078,10 @@ static int power_pmu_event_init(struct perf_event *event)
>> Â Â Â if (!ppmu)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> + Â Â /* does not support taken branch sampling */
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â switch (event->attr.type) {
>> Â Â Â case PERF_TYPE_HARDWARE:
>> Â Â Â Â Â Â Â ev = event->attr.config;
>> diff --git a/arch/sh/kernel/perf_event.c b/arch/sh/kernel/perf_event.c
>> index 10b14e3..068b8a2 100644
>> --- a/arch/sh/kernel/perf_event.c
>> +++ b/arch/sh/kernel/perf_event.c
>> @@ -310,6 +310,10 @@ static int sh_pmu_event_init(struct perf_event *event)
>> Â{
>> Â Â Â int err;
>>
>> + Â Â /* does not support taken branch sampling */
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â switch (event->attr.type) {
>> Â Â Â case PERF_TYPE_RAW:
>> Â Â Â case PERF_TYPE_HW_CACHE:
>> diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
>> index 614da62..8e16a4a 100644
>> --- a/arch/sparc/kernel/perf_event.c
>> +++ b/arch/sparc/kernel/perf_event.c
>> @@ -1105,6 +1105,10 @@ static int sparc_pmu_event_init(struct perf_event *event)
>> Â Â Â if (atomic_read(&nmi_active) < 0)
>> Â Â Â Â Â Â Â return -ENODEV;
>>
>> + Â Â /* does not support taken branch sampling */
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â switch (attr->type) {
>> Â Â Â case PERF_TYPE_HARDWARE:
>> Â Â Â Â Â Â Â if (attr->config >= sparc_pmu->max_events)
>> diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c
>> index 0397b23..0d8da03 100644
>> --- a/arch/x86/kernel/cpu/perf_event_amd.c
>> +++ b/arch/x86/kernel/cpu/perf_event_amd.c
>> @@ -138,6 +138,9 @@ static int amd_pmu_hw_config(struct perf_event *event)
>> Â Â Â if (ret)
>> Â Â Â Â Â Â Â return ret;
>>
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â if (event->attr.exclude_host && event->attr.exclude_guest)
>> Â Â Â Â Â Â Â /*
>> Â Â Â Â Â Â Â Â* When HO == GO == 1 the hardware treats that as GO == HO == 0
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index ed39225..36d1a63 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -5000,6 +5000,12 @@ static int perf_swevent_init(struct perf_event *event)
>> Â Â Â if (event->attr.type != PERF_TYPE_SOFTWARE)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> + Â Â /*
>> + Â Â Â* no branch sampling for software events
>> + Â Â Â*/
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â switch (event_id) {
>> Â Â Â case PERF_COUNT_SW_CPU_CLOCK:
>> Â Â Â case PERF_COUNT_SW_TASK_CLOCK:
>> @@ -5110,6 +5116,12 @@ static int perf_tp_event_init(struct perf_event *event)
>> Â Â Â if (event->attr.type != PERF_TYPE_TRACEPOINT)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> + Â Â /*
>> + Â Â Â* no branch sampling for tracepoint events
>> + Â Â Â*/
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â err = perf_trace_init(event);
>> Â Â Â if (err)
>> Â Â Â Â Â Â Â return err;
>> @@ -5335,6 +5347,12 @@ static int cpu_clock_event_init(struct perf_event *event)
>> Â Â Â if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> + Â Â /*
>> + Â Â Â* no branch sampling for software events
>> + Â Â Â*/
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â perf_swevent_init_hrtimer(event);
>>
>> Â Â Â return 0;
>> @@ -5409,6 +5427,12 @@ static int task_clock_event_init(struct perf_event *event)
>> Â Â Â if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> + Â Â /*
>> + Â Â Â* no branch sampling for software events
>> + Â Â Â*/
>> + Â Â if (has_branch_stack(event))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â perf_swevent_init_hrtimer(event);
>>
>> Â Â Â return 0;
>> diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
>> index b0309f7..cee5423 100644
>> --- a/kernel/events/hw_breakpoint.c
>> +++ b/kernel/events/hw_breakpoint.c
>> @@ -581,6 +581,12 @@ static int hw_breakpoint_event_init(struct perf_event *bp)
>> Â Â Â if (bp->attr.type != PERF_TYPE_BREAKPOINT)
>> Â Â Â Â Â Â Â return -ENOENT;
>>
>> + Â Â /*
>> + Â Â Â* no branch sampling for breakpoint events
>> + Â Â Â*/
>> + Â Â if (has_branch_stack(bp))
>> + Â Â Â Â Â Â return -EOPNOTSUPP;
>> +
>> Â Â Â err = register_perf_hw_breakpoint(bp);
>> Â Â Â if (err)
>> Â Â Â Â Â Â Â return err;
>
>
> --
> Linux Technology Centre
> IBM Systems and Technology Group
> Bangalore India
>
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