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Message-ID: <6476a228-847b-4804-9229-c11a881663c7@arm.com> Date: Fri, 26 Jul 2024 15:26:04 +0100 From: Suzuki K Poulose <suzuki.poulose@....com> To: Arnaldo Carvalho de Melo <acme@...nel.org>, James Clark <james.clark@...aro.org> Cc: coresight@...ts.linaro.org, gankulkarni@...amperecomputing.com, mike.leach@...aro.org, leo.yan@...ux.dev, anshuman.khandual@....com, James Clark <james.clark@....com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Maxime Coquelin <mcoquelin.stm32@...il.com>, Alexandre Torgue <alexandre.torgue@...s.st.com>, John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....com>, Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, "Liang, Kan" <kan.liang@...ux.intel.com>, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-stm32@...md-mailman.stormreply.com, linux-perf-users@...r.kernel.org Subject: Re: [PATCH v6 00/17] coresight: Use per-sink trace ID maps for Perf sessions Hi Arnaldo On 26/07/2024 15:18, Arnaldo Carvalho de Melo wrote: > On Mon, Jul 22, 2024 at 11:11:42AM +0100, James Clark wrote: >> This will allow sessions with more than CORESIGHT_TRACE_IDS_MAX ETMs >> as long as there are fewer than that many ETMs connected to each sink. > > Hey, may I take the tools part, i.e. patches 0-7 and someone on the ARM > kernel team pick the driver bits? I plan to pick the kernel driver bits for v6.12 Kind regards Suzuki > > - Arnaldo > >> Each sink owns its own trace ID map, and any Perf session connecting to >> that sink will allocate from it, even if the sink is currently in use by >> other users. This is similar to the existing behavior where the dynamic >> trace IDs are constant as long as there is any concurrent Perf session >> active. It's not completely optimal because slightly more IDs will be >> used than necessary, but the optimal solution involves tracking the PIDs >> of each session and allocating ID maps based on the session owner. This >> is difficult to do with the combination of per-thread and per-cpu modes >> and some scheduling issues. The complexity of this isn't likely to worth >> it because even with multiple users they'd just see a difference in the >> ordering of ID allocations rather than hitting any limits (unless the >> hardware does have too many ETMs connected to one sink). >> >> Per-thread mode works but only until there are any overlapping IDs, at >> which point Perf will error out. Both per-thread mode and sysfs mode are >> left to future changes, but both can be added on top of this initial >> implementation and only sysfs mode requires further driver changes. >> >> The HW_ID version field hasn't been bumped in order to not break Perf >> which already has an error condition for other values of that field. >> Instead a new minor version has been added which signifies that there >> are new fields but the old fields are backwards compatible. >> >> Changes since v5: >> >> * Hide queue number printout behind -v option >> * Style change in cs_etm__process_aux_output_hw_id() >> * Move new format enum to an earlier commit to reduce churn >> >> Changes since v4: >> >> * Fix compilation failure when TRACE_ID_DEBUG is set >> * Expand comment about not freeing individual trace IDs in >> free_event_data() >> >> Changes since v3: >> >> * Fix issue where trace IDs were overwritten by possibly invalid ones >> by Perf in unformatted mode. Now the HW_IDs are also used for >> unformatted mode unless the kernel didn't emit any. >> * Add a commit to check the OpenCSD version. >> * Add a commit to not save invalid IDs in the Perf header. >> * Replace cs_etm_queue's formatted and formatted_set members with a >> single enum which is easier to use. >> * Drop CORESIGHT_TRACE_ID_UNUSED_FLAG as it's no longer needed. >> * Add a commit to print the queue number in the raw dump. >> * Don't assert on the number of unformatted decoders if decoders == 0. >> >> >> Changes since v2: >> >> * Rebase on coresight-next 6.10-rc2 (b9b25c8496). >> * Fix double free of csdev if device registration fails. >> * Fix leak of coresight_trace_id_perf_start() if trace ID allocation >> fails. >> * Don't resend HW_ID for sink changes in per-thread mode. The existing >> CPU field on AUX records can be used to track this instead. >> * Tidy function doc for coresight_trace_id_release_all() >> * Drop first two commits now that they are in coresight-next >> * Add a commit to make the trace ID spinlock local to the map >> >> Changes since V1: >> >> * Rename coresight_device.perf_id_map to perf_sink_id_map. >> * Instead of outputting a HW_ID for each reachable ETM, output >> the sink ID and continue to output only the HW_ID once for >> each mapping. >> * Keep the first two Perf patches so that it applies cleanly >> on coresight-next, although they have been applied on perf-tools-next >> * Add new *_map() functions to the trace ID public API instead of >> modifying existing ones. >> * Collapse "coresight: Pass trace ID map into source enable" into >> "coresight: Use per-sink trace ID maps for Perf sessions" because the >> first commit relied on the default map being accessible which is no >> longer necessary due to the previous bullet point. >> >> >> James Clark (17): >> perf: cs-etm: Create decoders after both AUX and HW_ID search passes >> perf: cs-etm: Allocate queues for all CPUs >> perf: cs-etm: Move traceid_list to each queue >> perf: cs-etm: Create decoders based on the trace ID mappings >> perf: cs-etm: Only save valid trace IDs into files >> perf: cs-etm: Support version 0.1 of HW_ID packets >> perf: cs-etm: Print queue number in raw trace dump >> perf: cs-etm: Add runtime version check for OpenCSD >> coresight: Remove unused ETM Perf stubs >> coresight: Clarify comments around the PID of the sink owner >> coresight: Move struct coresight_trace_id_map to common header >> coresight: Expose map arguments in trace ID API >> coresight: Make CPU id map a property of a trace ID map >> coresight: Use per-sink trace ID maps for Perf sessions >> coresight: Remove pending trace ID release mechanism >> coresight: Emit sink ID in the HW_ID packets >> coresight: Make trace ID map spinlock local to the map >> >> drivers/hwtracing/coresight/coresight-core.c | 37 +- >> drivers/hwtracing/coresight/coresight-dummy.c | 3 +- >> .../hwtracing/coresight/coresight-etm-perf.c | 43 +- >> .../hwtracing/coresight/coresight-etm-perf.h | 18 - >> .../coresight/coresight-etm3x-core.c | 9 +- >> .../coresight/coresight-etm4x-core.c | 9 +- >> drivers/hwtracing/coresight/coresight-priv.h | 1 + >> drivers/hwtracing/coresight/coresight-stm.c | 3 +- >> drivers/hwtracing/coresight/coresight-sysfs.c | 3 +- >> .../hwtracing/coresight/coresight-tmc-etr.c | 5 +- >> drivers/hwtracing/coresight/coresight-tmc.h | 5 +- >> drivers/hwtracing/coresight/coresight-tpdm.c | 3 +- >> .../hwtracing/coresight/coresight-trace-id.c | 138 ++-- >> .../hwtracing/coresight/coresight-trace-id.h | 70 +- >> include/linux/coresight-pmu.h | 17 +- >> include/linux/coresight.h | 21 +- >> tools/build/feature/test-libopencsd.c | 4 +- >> tools/include/linux/coresight-pmu.h | 17 +- >> tools/perf/Makefile.config | 2 +- >> tools/perf/arch/arm/util/cs-etm.c | 11 +- >> .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 49 +- >> .../perf/util/cs-etm-decoder/cs-etm-decoder.h | 3 +- >> .../util/cs-etm-decoder/cs-etm-min-version.h | 13 + >> tools/perf/util/cs-etm.c | 629 +++++++++++------- >> tools/perf/util/cs-etm.h | 12 +- >> 25 files changed, 650 insertions(+), 475 deletions(-) >> create mode 100644 tools/perf/util/cs-etm-decoder/cs-etm-min-version.h >> >> -- >> 2.34.1
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