Messages in this thread | | | Subject | Re: [PATCH 00/13] Add support for perf_arch_regs | From | Madhavan Srinivasan <> | Date | Thu, 1 Sep 2016 08:38:56 +0530 |
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On Tuesday 30 August 2016 09:31 PM, Nilay Vaish wrote: > On 28 August 2016 at 16:00, Madhavan Srinivasan > <maddy@linux.vnet.ibm.com> wrote: >> Patchset to extend PERF_SAMPLE_REGS_INTR to include >> platform specific PMU registers. >> >> Patchset applies cleanly on tip:perf/core branch >> >> It's a perennial request from hardware folks to be able to >> see the raw values of the pmu registers. Partly it's so that >> they can verify perf is doing what they want, and some >> of it is that they're interested in some of the more obscure >> info that isn't plumbed out through other perf interfaces. >> >> Over the years internally we have used various hack to get >> the requested data out but this is an attempt to use a >> somewhat standard mechanism (using PERF_SAMPLE_REGS_INTR). >> >> This would also be helpful for those of us working on the perf >> hardware backends, to be able to verify that we're programming >> things correctly, without resorting to debug printks etc. >> >> Mechanism proposed: >> >> 1)perf_regs structure is extended with a perf_arch_regs structure >> which each arch/ can populate with their specific platform >> registers to sample on each perf interrupt and an arch_regs_mask >> variable, which is for perf tool to know about the perf_arch_regs >> that are supported. >> >> 2)perf/core func perf_sample_regs_intr() extended to update >> the perf_arch_regs structure and the perf_arch_reg_mask. Set of new >> support functions added perf_get_arch_regs_mask() and >> perf_get_arch_reg() to aid the updates from arch/ side. >> >> 3) perf/core funcs perf_prepare_sample() and perf_output_sample() >> are extended to support the update for the perf_arch_regs_mask and >> perf_arch_regs in the sample >> >> 4)perf/core func perf_output_sample_regs() extended to dump >> the arch_regs to the output sample. >> >> 5)Finally, perf tool side is updated to include a new element >> "arch_regs_mask" in the "struct regs_dump", event sample funcs >> and print functions are updated to support perf_arch_regs. >> > I read the patch series and I have one suggestion to make. I think we > should not use 'arch regs' to refer to these pmu registers. I think Reason is that they are arch specific pmu regs. But I guess we can go with pmu_regs also. And having a "pregs" as option to list in -I? will be fine? (patch 13 in the patch series)
Maddy
> architectural registers typically refer to the ones that hold the > state of the process. Can we replace arch_regs by pmu_regs, or some > other choice? > > Thanks > Nilay >
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