Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 31 Jan 2023 11:49:13 +0000 | Subject | Re: [PATCH v7 00/15] coresight: Add new API to allocate trace source ID values | From | Suzuki K Poulose <> |
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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
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