Re: [PATCH 0/8] Add support for PowerPC Hypervisor supplied performance counters
On 01/22/2014 04:11 PM, Cody P Schafer wrote:
On 01/21/2014 05:32 PM, Michael Ellerman wrote:
On Thu, 2014-01-16 at 15:53 -0800, Cody P Schafer wrote:
These patches add basic pmus for 2 powerpc hypervisor interfaces to obtain
performance counters: gpci ("get performance counter info") and 24x7.
Any comments on/things that need fixing for this patch set to be merged?
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Re: [PATCH 0/8] Add support for PowerPC Hypervisor supplied performance counters
On 01/21/2014 05:32 PM, Michael Ellerman wrote:
> On Thu, 2014-01-16 at 15:53 -0800, Cody P Schafer wrote:
>> These patches add basic pmus for 2 powerpc hypervisor interfaces to obtain
>> performance counters: gpci ("get performance counter info") and 24x7.
>>
>> The counters supplied by these interfaces are continually counting and never
>> need to be (and cannot be) disabled or enabled. They additionally do not
>> generate any interrupts. This makes them in some regards similar to software
>> counters, and as a result their implimentation shares some common code (which
>> an initial patch exposes) with the sw counters.
>
> Hi Cody,
>
> Can you please add some more explanation of this series.
Sure
> In particular why do we need two new PMUs, and how do they relate to each
> other?
These 2 PMUs end up providing access to some cpu, core, and chip level counters
not
exposed via other interfaces, and additionally allow monitoring the performance
of
other lpars (guests) on the same host system. Because it provides access to
core and
chip level counters, this pair of PMUs could be thought of as powerpc's
counterpart
to x86's uncore events.
As an example, "processor_bus_utilization_abc" and
"processor_bus_utilization_wxyz"
(in hv_gpci.h) allow retreval of total cycles and idle cycles for various
inter-chip buses.
GPCI is an interface that already exists on some power7 machines (depending on
the fw
version), but is rather in-flexible and code intensive to add additional
counters to.
The 24x7 interfaces currently are designed to co-exist with the gpci interface
while
replacing most of gpci's functionality on newer systems. Right now, the 24x7
code I've
submitted uses the gpci calls to check if it has permission to access certain
classes
of counters.
> And can you add an example of how I'd actually use them using perf.
# For gpci (formed from reading hv_gpci.h), gets
"processor_time_in_timebase_cycles"
perf stat -e
'hv_gpci/counter_info_version=3,offset=0,length=8,secondary_index=0,starting_index=0x,request=0x10/'
-r 0 -a -x ' ' sleep 0.1
# For 24x7, assuming access to hw+fw that supports it, gets a yet-to-be
identified counter:
perf stat -e 'hv_24x7/domain=2,offset=8,starting_index=0,lpar=0x/' -r 0
-C 0 -x ' ' sleep 0.1
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Re: [PATCH 0/8] Add support for PowerPC Hypervisor supplied performance counters
On 01/22/2014 07:02 AM, Michael Ellerman wrote:
> On Thu, 2014-01-16 at 15:53 -0800, Cody P Schafer wrote:
>> These patches add basic pmus for 2 powerpc hypervisor interfaces to obtain
>> performance counters: gpci ("get performance counter info") and 24x7.
>>
>> The counters supplied by these interfaces are continually counting and never
>> need to be (and cannot be) disabled or enabled. They additionally do not
>> generate any interrupts. This makes them in some regards similar to software
>> counters, and as a result their implimentation shares some common code (which
>> an initial patch exposes) with the sw counters.
>
> Hi Cody,
>
> Can you please add some more explanation of this series.
>
> In particular why do we need two new PMUs, and how do they relate to each
> other?
>
> And can you add an example of how I'd actually use them using perf.
>
Yeah, agreed.
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Re: [PATCH 0/8] Add support for PowerPC Hypervisor supplied performance counters
On Thu, 2014-01-16 at 15:53 -0800, Cody P Schafer wrote:
> These patches add basic pmus for 2 powerpc hypervisor interfaces to obtain
> performance counters: gpci ("get performance counter info") and 24x7.
>
> The counters supplied by these interfaces are continually counting and never
> need to be (and cannot be) disabled or enabled. They additionally do not
> generate any interrupts. This makes them in some regards similar to software
> counters, and as a result their implimentation shares some common code (which
> an initial patch exposes) with the sw counters.
Hi Cody,
Can you please add some more explanation of this series.
In particular why do we need two new PMUs, and how do they relate to each
other?
And can you add an example of how I'd actually use them using perf.
cheers
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[PATCH 0/8] Add support for PowerPC Hypervisor supplied performance counters
These patches add basic pmus for 2 powerpc hypervisor interfaces to obtain
performance counters: gpci ("get performance counter info") and 24x7.
The counters supplied by these interfaces are continually counting and never
need to be (and cannot be) disabled or enabled. They additionally do not
generate any interrupts. This makes them in some regards similar to software
counters, and as a result their implimentation shares some common code (which
an initial patch exposes) with the sw counters.
There is ongoing work to support transactions for each of these pmus.
Cody P Schafer (8):
perf: add PMU_RANGE_ATTR() helper for use by sw-like pmus
perf core: export swevent hrtimer helpers
powerpc: add hvcalls for 24x7 and gpci (get performance counter info)
powerpc: add hv_gpci interface header
powerpc: add 24x7 interface header
powerpc/perf: add support for the hv gpci (get performance counter
info) interface
powerpc/perf: add support for the hv 24x7 interface
powerpc/perf: add kconfig option for hypervisor provided counters
arch/powerpc/include/asm/hv_24x7.h | 239
arch/powerpc/include/asm/hv_gpci.h | 490 +
arch/powerpc/include/asm/hvcall.h | 6 +-
arch/powerpc/perf/Makefile | 2 +
arch/powerpc/perf/hv-24x7.c| 354
arch/powerpc/perf/hv-gpci.c| 235
arch/powerpc/platforms/Kconfig.cputype | 6 +
include/linux/perf_event.h | 22 +-
kernel/events/core.c | 8 +-
9 files changed, 1356 insertions(+), 6 deletions(-)
create mode 100644 arch/powerpc/include/asm/hv_24x7.h
create mode 100644 arch/powerpc/include/asm/hv_gpci.h
create mode 100644 arch/powerpc/perf/hv-24x7.c
create mode 100644 arch/powerpc/perf/hv-gpci.c
--
1.8.5.2
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