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[SPE] Check for SPE sample record format version #25

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PrzemekWirkus opened this issue Oct 14, 2024 · 0 comments
Open

[SPE] Check for SPE sample record format version #25

PrzemekWirkus opened this issue Oct 14, 2024 · 0 comments
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enhancement New feature or request

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@PrzemekWirkus
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PrzemekWirkus commented Oct 14, 2024

The Statistical Profiling Extension sample record format version is identified by PMSIDR_EL1.Format. The
architecture currently defines only version 0.

Note:

Armv8.7 defines the SPE sample record format version, allowing future architecture updates to extend or change
the record format. PMSIDR_EL1.Format was previously a RES0 field in a read-only register. Software that reads
and checks PMSIDR_EL1.Format on any implementation prior to Armv8.7 that includes SPE will read a value
indicating format version 0 is supported.
The sample record format version 0 is self-describing and extensible. This format allows software to parse profile
data even when that profile data contains extended information.

DOD:

  • Check in wperf-driver SPE sample record version and yield Kernel log with incompatible version (if applicable).
  • wperf should check HW_CFG flag spe_device.pmsidr_el1_value and warn users that we do not support SPE parser for spe_device.pmsidr_el1_value > 0.

PMSIDR_EL1, Sampling Profiling ID Register

@PrzemekWirkus PrzemekWirkus added the enhancement New feature or request label Oct 14, 2024
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