Messages in this thread | | | Date | Mon, 20 Feb 2023 16:24:39 +0000 | Subject | v4: Re: [PATCH v7 00/15] coresight: Add new API to allocate trace source ID values | From | Suzuki K Poulose <> |
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Arnaldo
Gentle ping
On 31/01/2023 11:49, Suzuki K Poulose wrote: > Hi Arnaldo > > On 24/01/2023 11:36, Suzuki K Poulose wrote: >> Hi Arnaldo >> >> Gentle ping. >> >> On 19/01/2023 12:00, Suzuki K Poulose wrote: >>> Hi Arnaldo, >>> >>> On 16/01/2023 12:49, Mike Leach wrote: >>>> The current method for allocating trace source ID values to sources is >>>> to use a fixed algorithm for CPU based sources of (cpu_num * 2 + 0x10). >>>> The STM is allocated ID 0x1. >>>> >>>> This fixed algorithm is used in both the CoreSight driver code, and by >>>> perf when writing the trace metadata in the AUXTRACE_INFO record. >>>> >>>> The method needs replacing as currently:- >>>> 1. It is inefficient in using available IDs. >>>> 2. Does not scale to larger systems with many cores and the algorithm >>>> has no limits so will generate invalid trace IDs for cpu number > 44. >>>> >>>> Additionally requirements to allocate additional system IDs on some >>>> systems have been seen. >>>> >>>> This patch set introduces an API that allows the allocation of >>>> trace IDs >>>> in a dynamic manner. >>>> >>>> Architecturally reserved IDs are never allocated, and the system is >>>> limited to allocating only valid IDs. >>>> >>>> Each of the current trace sources ETM3.x, ETM4.x and STM is updated >>>> to use >>>> the new API. >>>> >>>> For the ETMx.x devices IDs are allocated on certain events >>>> a) When using sysfs, an ID will be allocated on hardware enable, or >>>> a read of >>>> sysfs TRCTRACEID register and freed when the sysfs reset is written. >>>> >>>> b) When using perf, ID is allocated on during setup AUX event, and >>>> freed on >>>> event free. IDs are communicated using the AUX_OUTPUT_HW_ID packet. >>>> The ID allocator is notified when perf sessions start and stop >>>> so CPU based IDs are kept constant throughout any perf session. >>>> >>>> >>>> Note: This patchset breaks some backward compatibility for perf >>>> record and >>>> perf report. >>>> >>>> The version of the AUXTRACE_INFO has been updated to reflect the >>>> fact that >>>> the trace source IDs are generated differently. This will >>>> mean older versions of perf report cannot decode the newer file. >>>> >>>> Appies to coresight/next >>>> >> >> ... >> >>>> Mike Leach (15): >>>> coresight: trace-id: Add API to dynamically assign Trace ID values >>>> coresight: Remove obsolete Trace ID unniqueness checks >>>> coresight: perf: traceid: Add perf ID allocation and notifiers >>>> coresight: stm: Update STM driver to use Trace ID API >>>> coresight: etm4x: Update ETM4 driver to use Trace ID API >>>> coresight: etm3x: Update ETM3 driver to use Trace ID API >>>> coresight: etmX.X: stm: Remove trace_id() callback >>>> coresight: trace id: Remove legacy get trace ID function. >>>> perf: cs-etm: Move mapping of Trace ID and cpu into helper function >>>> perf: cs-etm: Update record event to use new Trace ID protocol >>>> kernel: events: Export perf_report_aux_output_id() >>>> perf: cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet >>>> coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID >>>> coresight: trace-id: Add debug & test macros to Trace ID allocation >>>> coresight: etm3x: docs: Alter sysfs documentation for trace id >>>> updates >>> >>> I have pushed the kernel patches on this series to coresight tree >>> next[0]. >>> >>> I will be sending them out to Greg for v6.3. Please could you queue the >>> perf tool changes in the series ? i.e., Patches 9,10 and 12. >>> >>> >>> [0] >>> https://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git/log/?h=next >>> >> >> Please could you pick up the perf tool changes above ? > > Please could you confirm if you are able to queue the perf tool changes > ? Or would you like me route it via coresight tree ? > > Kind regards > Suzuki >
Suzuki
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