Using SPM

Using SPM#

SPM (Streaming Performance Monitor) sampling service for GPU profiling is a profiling technique to periodically sample performance counters with GPU timestamp.

Here are the benefits of using SPM to sample counters:

  • Identify performance bottlenecks

  • Understand kernel execution behavior

  • fine-grained, time-resolved performance data.

To try out the SPM, you can use the command-line tool rocprofv3 or the ROCprofiler-SDK library.

SPM is one of three hardware counter collection mechanisms in ROCprofiler-SDK, alongside dispatch PMC and device counter collection. For a comparison of granularity, timing, and use cases, see How SPM differs from other counter services in the SDK overview.

SPM availability and configuration#

To check counters that can be sampled, use:

rocprofv3 -L

Or

rocprofv3 --list-avail

The output lists if rocprofv3 supports SPM

Counter_Name        :   TCC_MISS
Description         :   Number of cache misses. UC reads count as misses.
Block               :   TCC
SPM                 :   Supported
Dimensions          :   DIMENSION_INSTANCE[0:15] DIMENSION_XCC[0:7]

The preceding output shows that the TCC_MISS counter can be sampled.

Note

For proper functioning, SPM requires AMD GPU Driver version 6.19.14.31400000 or later. Before using SPM, verify the loaded amdgpu kernel module version.

To check the driver version, use:

cat /sys/module/amdgpu/version

# Example output:
# 6.19.14.31400000

You can also check this driver version using amd-smi version command on DKMS-built systems.

Use the following command to use SPM:

rocprofv3 --spm-beta-enabled --spm SQ_WAVES --spm-sample-interval-unit sclk_cycles --spm-sample-interval 1200  --output-format json -- <application_path>

The preceding command enables SPM for SQ_WAVES and sample interval with unit as sclk cycle counts. Replace <application_path> with the path to the application you want to profile. This generates a JSON results file prefixed with the process ID.

CLI options#

Use the following options to enable and configure SPM collection with rocprofv3, or query SPM support per agent with rocprofv3-avail.

Tool

Option

Description

Example

rocprofv3

--spm-beta-enabled

Required to enable SPM collection

rocprofv3 --spm-beta-enabled --spm SQ_WAVES -- ./my_app

--spm <COUNTERS>

Counters to collect; all must fit in a single hardware pass

rocprofv3 --spm-beta-enabled --spm SQ_WAVES,SQ_BUSY_CYCLES -- ./my_app

--spm-sample-interval <N>

Sampling interval in sclk_cycles

rocprofv3 --spm-beta-enabled --spm SQ_WAVES --spm-sample-interval 500 -- ./my_app

--spm-sample-interval-unit <UNIT>

Interval unit; currently accepts sclk_cycles only

rocprofv3 --spm-beta-enabled --spm SQ_WAVES --spm-sample-interval-unit sclk_cycles -- ./my_app

rocprofv3-avail

list --spm

Lists SPM-capable counters per agent

rocprofv3-avail list --spm

list --spm-config

Lists agents with SPM configuration support, including minimum and maximum sampling intervals

rocprofv3-avail list --spm-config

rocprofv3-avail is a companion tool that queries which counters support SPM, and which agents support SPM configuration, without collecting a trace. See Using rocprofv3-avail for full usage details.

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