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X-CSE-ConnectionGUID: UHyr8G7xTEe9UdCzxih/4A== X-CSE-MsgGUID: wRzh3eBTQ4WQJ//XkvgPAw== X-IronPort-AV: E=McAfee;i="6700,10204,11245"; a="29832197" X-IronPort-AV: E=Sophos;i="6.11,256,1725346800"; d="scan'208";a="29832197" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2024 02:12:04 -0800 X-CSE-ConnectionGUID: cgqXwjL9QR+kmFyCZNdqIQ== X-CSE-MsgGUID: Qjmd+TnCRs25GjKf0TAP8w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,256,1725346800"; d="scan'208";a="88124969" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.246.16.81]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2024 02:11:56 -0800 Message-ID: <0b073156-dbf4-420e-b6e2-98d404ba38f1@intel.com> Date: Mon, 4 Nov 2024 12:11:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V14 00/11] perf/core: Add ability for an event to "pause" or "resume" AUX area tracing From: Adrian Hunter To: Peter Zijlstra Cc: Ingo Molnar , Mark Rutland , Alexander Shishkin , Heiko Carstens , Thomas Richter , Hendrik Brueckner , Suzuki K Poulose , Mike Leach , James Clark , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Yicong Yang , Jonathan Cameron , Will Deacon , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Ian Rogers , Andi Kleen , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, H Peter Anvin , Kan Liang , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org References: <20241022155920.17511-1-adrian.hunter@intel.com> <7bacbe72-c283-453b-bf1f-6ba05b68cac8@intel.com> Content-Language: en-US Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <7bacbe72-c283-453b-bf1f-6ba05b68cac8@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241104_021204_857754_15C69E4D X-CRM114-Status: GOOD ( 35.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 30/10/24 15:16, Adrian Hunter wrote: > On 22/10/24 18:59, Adrian Hunter wrote: >> Hi >> >> Note for V14: >> KVM patches dropped. > > ping ping > >> >> Note for V12: >> There was a small conflict between the Intel PT changes in >> "KVM: x86: Fix Intel PT Host/Guest mode when host tracing" and the >> changes in this patch set, so I have put the patch sets together, >> along with outstanding fix "perf/x86/intel/pt: Fix buffer full but >> size is 0 case" >> >> Cover letter for KVM changes (patches 2 to 4): >> >> There is a long-standing problem whereby running Intel PT on host and guest >> in Host/Guest mode, causes VM-Entry failure. >> >> The motivation for this patch set is to provide a fix for stable kernels >> prior to the advent of the "Mediated Passthrough vPMU" patch set: >> >> https://lore.kernel.org/kvm/20240801045907.4010984-1-mizhang@google.com/ >> >> which would render a large part of the fix unnecessary but likely not be >> suitable for backport to stable due to its size and complexity. >> >> Ideally, this patch set would be applied before "Mediated Passthrough vPMU" >> >> Note that the fix does not conflict with "Mediated Passthrough vPMU", it >> is just that "Mediated Passthrough vPMU" will make the code to stop and >> restart Intel PT unnecessary. >> >> Note for V11: >> Moving aux_paused into a union within struct hw_perf_event caused >> a regression because aux_paused was being written unconditionally >> even though it is valid only for AUX (e.g. Intel PT) PMUs. >> That is fixed in V11. >> >> Hardware traces, such as instruction traces, can produce a vast amount of >> trace data, so being able to reduce tracing to more specific circumstances >> can be useful. >> >> The ability to pause or resume tracing when another event happens, can do >> that. >> >> These patches add such a facilty and show how it would work for Intel >> Processor Trace. >> >> Maintainers of other AUX area tracing implementations are requested to >> consider if this is something they might employ and then whether or not >> the ABI would work for them. Note, thank you to James Clark (ARM) for >> evaluating the API for Coresight. Suzuki K Poulose (ARM) also responded >> positively to the RFC. >> >> Changes to perf tools are now (since V4) fleshed out. >> >> Please note, Intel® Architecture Instruction Set Extensions and Future >> Features Programming Reference March 2024 319433-052, currently: >> >> https://cdrdv2.intel.com/v1/dl/getContent/671368 >> >> introduces hardware pause / resume for Intel PT in a feature named >> Intel PT Trigger Tracing. >> >> For that more fields in perf_event_attr will be necessary. The main >> differences are: >> - it can be applied not just to overflows, but optionally to >> every event >> - a packet is emitted into the trace, optionally with IP >> information >> - no PMI >> - works with PMC and DR (breakpoint) events only >> >> Here are the proposed additions to perf_event_attr, please comment: >> >> diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h >> index 0c557f0a17b3..05dcc43f11bb 100644 >> --- a/tools/include/uapi/linux/perf_event.h >> +++ b/tools/include/uapi/linux/perf_event.h >> @@ -369,6 +369,22 @@ enum perf_event_read_format { >> PERF_FORMAT_MAX = 1U << 5, /* non-ABI */ >> }; >> >> +enum { >> + PERF_AUX_ACTION_START_PAUSED = 1U << 0, >> + PERF_AUX_ACTION_PAUSE = 1U << 1, >> + PERF_AUX_ACTION_RESUME = 1U << 2, >> + PERF_AUX_ACTION_EMIT = 1U << 3, >> + PERF_AUX_ACTION_NR = 0x1f << 4, >> + PERF_AUX_ACTION_NO_IP = 1U << 9, >> + PERF_AUX_ACTION_PAUSE_ON_EVT = 1U << 10, >> + PERF_AUX_ACTION_RESUME_ON_EVT = 1U << 11, >> + PERF_AUX_ACTION_EMIT_ON_EVT = 1U << 12, >> + PERF_AUX_ACTION_NR_ON_EVT = 0x1f << 13, >> + PERF_AUX_ACTION_NO_IP_ON_EVT = 1U << 18, >> + PERF_AUX_ACTION_MASK = ~PERF_AUX_ACTION_START_PAUSED, >> + PERF_AUX_PAUSE_RESUME_MASK = PERF_AUX_ACTION_PAUSE | PERF_AUX_ACTION_RESUME, >> +}; >> + >> #define PERF_ATTR_SIZE_VER0 64 /* sizeof first published struct */ >> #define PERF_ATTR_SIZE_VER1 72 /* add: config2 */ >> #define PERF_ATTR_SIZE_VER2 80 /* add: branch_sample_type */ >> @@ -515,10 +531,19 @@ struct perf_event_attr { >> union { >> __u32 aux_action; >> struct { >> - __u32 aux_start_paused : 1, /* start AUX area tracing paused */ >> - aux_pause : 1, /* on overflow, pause AUX area tracing */ >> - aux_resume : 1, /* on overflow, resume AUX area tracing */ >> - __reserved_3 : 29; >> + __u32 aux_start_paused : 1, /* start AUX area tracing paused */ >> + aux_pause : 1, /* on overflow, pause AUX area tracing */ >> + aux_resume : 1, /* on overflow, resume AUX area tracing */ >> + aux_emit : 1, /* generate AUX records instead of events */ >> + aux_nr : 5, /* AUX area tracing reference number */ >> + aux_no_ip : 1, /* suppress IP in AUX records */ >> + /* Following apply to event occurrence not overflows */ >> + aux_pause_on_evt : 1, /* on event, pause AUX area tracing */ >> + aux_resume_on_evt : 1, /* on event, resume AUX area tracing */ >> + aux_emit_on_evt : 1, /* generate AUX records instead of events */ >> + aux_nr_on_evt : 5, /* AUX area tracing reference number */ >> + aux_no_ip_on_evt : 1, /* suppress IP in AUX records */ >> + __reserved_3 : 13; >> }; >> }; >> >> >> Changes in V14: >> Dropped KVM patches >> >> perf/x86/intel/pt: Add support for pause / resume >> Set pt->handle_nmi after configuration is completed instead of during >> >> Changes in V13: >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Do aux_resume at the end of __perf_event_overflow() so as to trace >> less of perf itself >> >> perf tools: Add missing_features for aux_start_paused, aux_pause, aux_resume >> Add error message also in EOPNOTSUPP case (Leo) >> >> Changes in V12: >> Add previously sent patch "perf/x86/intel/pt: Fix buffer full >> but size is 0 case" >> >> Add previously sent patch set "KVM: x86: Fix Intel PT Host/Guest >> mode when host tracing" >> >> Rebase on current tip plus patch set "KVM: x86: Fix Intel PT Host/Guest >> mode when host tracing" >> >> Changes in V11: >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Make assignment to event->hw.aux_paused conditional on >> (pmu->capabilities & PERF_PMU_CAP_AUX_PAUSE). >> >> perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling >> Remove definition of has_aux_action() because it has >> already been added as an inline function. >> >> perf/x86/intel/pt: Fix sampling synchronization >> perf tools: Enable evsel__is_aux_event() to work for ARM/ARM64 >> perf tools: Enable evsel__is_aux_event() to work for S390_CPUMSF >> Dropped because they have already been applied >> >> Changes in V10: >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Move aux_paused into a union within struct hw_perf_event. >> Additional comment wrt PERF_EF_PAUSE/PERF_EF_RESUME. >> Factor out has_aux_action() as an inline function. >> Use scoped_guard for irqsave. >> Move calls of perf_event_aux_pause() from __perf_event_output() >> to __perf_event_overflow(). >> >> Changes in V9: >> perf/x86/intel/pt: Fix sampling synchronization >> New patch >> >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Move aux_paused to struct hw_perf_event >> >> perf/x86/intel/pt: Add support for pause / resume >> Add more comments and barriers for resume_allowed and >> pause_allowed >> Always use WRITE_ONCE with resume_allowed >> >> >> Changes in V8: >> >> perf tools: Parse aux-action >> Fix clang warning: >> util/auxtrace.c:821:7: error: missing field 'aux_action' initializer [-Werror,-Wmissing-field-initializers] >> 821 | {NULL}, >> | ^ >> >> Changes in V7: >> >> Add Andi's Reviewed-by for patches 2-12 >> Re-base >> >> Changes in V6: >> >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Removed READ/WRITE_ONCE from __perf_event_aux_pause() >> Expanded comment about guarding against NMI >> >> Changes in V5: >> >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Added James' Ack >> >> perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling >> New patch >> >> perf tools >> Added Ian's Ack >> >> Changes in V4: >> >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> Rename aux_output_cfg -> aux_action >> Reorder aux_action bits from: >> aux_pause, aux_resume, aux_start_paused >> to: >> aux_start_paused, aux_pause, aux_resume >> Fix aux_action bits __u64 -> __u32 >> >> coresight: Have a stab at support for pause / resume >> Dropped >> >> perf tools >> All new patches >> >> Changes in RFC V3: >> >> coresight: Have a stab at support for pause / resume >> 'mode' -> 'flags' so it at least compiles >> >> Changes in RFC V2: >> >> Use ->stop() / ->start() instead of ->pause_resume() >> Move aux_start_paused bit into aux_output_cfg >> Tighten up when Intel PT pause / resume is allowed >> Add an example of how it might work for CoreSight >> >> >> Adrian Hunter (11): >> perf/x86/intel/pt: Fix buffer full but size is 0 case >> perf/core: Add aux_pause, aux_resume, aux_start_paused >> perf/x86/intel/pt: Add support for pause / resume >> perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling >> perf tools: Add aux_start_paused, aux_pause and aux_resume >> perf tools: Add aux-action config term >> perf tools: Parse aux-action >> perf tools: Add missing_features for aux_start_paused, aux_pause, aux_resume >> perf intel-pt: Improve man page format >> perf intel-pt: Add documentation for pause / resume >> perf intel-pt: Add a test for pause / resume >> >> arch/x86/events/intel/core.c | 4 +- >> arch/x86/events/intel/pt.c | 84 +++- >> arch/x86/events/intel/pt.h | 6 + >> include/linux/perf_event.h | 28 ++ >> include/uapi/linux/perf_event.h | 11 +- >> kernel/events/core.c | 75 +++- >> kernel/events/internal.h | 1 + >> tools/include/uapi/linux/perf_event.h | 11 +- >> tools/perf/Documentation/perf-intel-pt.txt | 596 ++++++++++++++++++----------- >> tools/perf/Documentation/perf-record.txt | 4 + >> tools/perf/builtin-record.c | 4 +- >> tools/perf/tests/shell/test_intel_pt.sh | 28 ++ >> tools/perf/util/auxtrace.c | 67 +++- >> tools/perf/util/auxtrace.h | 6 +- >> tools/perf/util/evsel.c | 15 + >> tools/perf/util/evsel.h | 1 + >> tools/perf/util/evsel_config.h | 1 + >> tools/perf/util/parse-events.c | 10 + >> tools/perf/util/parse-events.h | 1 + >> tools/perf/util/parse-events.l | 1 + >> tools/perf/util/perf_event_attr_fprintf.c | 3 + >> tools/perf/util/pmu.c | 1 + >> 22 files changed, 716 insertions(+), 242 deletions(-) >> >> >> Regards >> Adrian >