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Date: Thu, 26 May 2022 16:29:22 +0530 From: Ravi Bangoria <ravi.bangoria@....com> To: Peter Zijlstra <peterz@...radead.org> Cc: acme@...nel.org, jolsa@...nel.org, namhyung@...nel.org, eranian@...gle.com, irogers@...gle.com, jmario@...hat.com, leo.yan@...aro.org, alisaidi@...zon.com, ak@...ux.intel.com, kan.liang@...ux.intel.com, dave.hansen@...ux.intel.com, hpa@...or.com, mingo@...hat.com, mark.rutland@....com, alexander.shishkin@...ux.intel.com, tglx@...utronix.de, bp@...en8.de, x86@...nel.org, linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, sandipan.das@....com, ananth.narayan@....com, kim.phillips@....com, santosh.shukla@....com, Ravi Bangoria <ravi.bangoria@....com> Subject: Re: [PATCH 06/13] perf/x86/amd: Support PERF_SAMPLE_PHY_ADDR using IBS_DC_PHYSADDR On 26-May-22 3:26 PM, Peter Zijlstra wrote: > On Thu, May 26, 2022 at 02:16:28PM +0530, Ravi Bangoria wrote: >> On 25-May-22 4:51 PM, Peter Zijlstra wrote: >>> On Wed, May 25, 2022 at 03:09:31PM +0530, Ravi Bangoria wrote: >>>> IBS_DC_PHYSADDR provides the physical data address for the tagged load/ >>>> store operation. Populate perf sample physical address using it. >>>> >>>> Signed-off-by: Ravi Bangoria <ravi.bangoria@....com> >>>> --- >>>> arch/x86/events/amd/ibs.c | 26 +++++++++++++++++++++++++- >>>> 1 file changed, 25 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c >>>> index b57736357e25..c719020c0e83 100644 >>>> --- a/arch/x86/events/amd/ibs.c >>>> +++ b/arch/x86/events/amd/ibs.c >>>> @@ -986,13 +986,35 @@ static void perf_ibs_get_data_addr(struct perf_event *event, >>>> data->addr = ibs_data->regs[ibs_op_msr_idx(MSR_AMD64_IBSDCLINAD)]; >>>> } >>>> >>>> +static void perf_ibs_get_phy_addr(struct perf_event *event, >>>> + struct perf_ibs_data *ibs_data, >>>> + struct perf_sample_data *data) >>>> +{ >>>> + union perf_mem_data_src *data_src = &data->data_src; >>>> + u64 op_data3 = ibs_data->regs[ibs_op_msr_idx(MSR_AMD64_IBSOPDATA3)]; >>>> + u64 phy_addr_valid = op_data3 & IBS_DC_PHY_ADDR_VALID_MASK; >>>> + >>>> + if (!(event->attr.sample_type & PERF_SAMPLE_DATA_SRC)) >>>> + perf_ibs_get_mem_op(op_data3, data); >>>> + >>>> + if ((data_src->mem_op != PERF_MEM_OP_LOAD && >>>> + data_src->mem_op != PERF_MEM_OP_STORE) || >>>> + !phy_addr_valid) { >>>> + data->phys_addr = 0x0; >>>> + return; >>>> + } >>>> + >>>> + data->phys_addr = ibs_data->regs[ibs_op_msr_idx(MSR_AMD64_IBSDCPHYSAD)]; >>>> +} >>> >>> perf_prepare_sample() will unconditionally overwrite data->phys_addr. >>> There is currently no facility to let the driver set this field. >> >> Thanks for pointing it Peter. Would you mind if I add: > > I think it's best if you extend/mimic the __PERF_SAMPLE_CALLCHAIN_EARLY > hack. It's more or less the same problem and then at least the solution > is consistent. I've one more identical optimization in my list. IBS_OP_DATA3[IbsDcPgSz] can provide PERF_SAMPLE_DATA_PAGE_SIZE. I hope consuming two more bits for internal purpose is okay. Thanks, Ravi
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