Hello, This patch set implements initial support for performance counter sampling in Panthor, as a follow-up for Adrián Larumbe's patch set [1]. This version of the patch series fixes a number of issues, including FW ring buffer wrapping and IRQ handling for the performance counter IRQs. The size of the sample is also added to the uAPI, allowing for the PERF_INFO DEV_QUERY to be sufficient to handle backwards and forwards compatibility of the interface. The Mesa implementation is also now available [3].
Existing performance counter workflows, such as those in game engines, and user-space power models/governor implementations require the ability to simultaneously obtain counter data. The hardware and firmware interfaces support a single global configuration, meaning the kernel must allow for the multiplexing. It is also in the best position to supplement the counter data with contextual information about elapsed sampling periods, information on the power state transitions undergone during the sampling period, and cycles elapsed on specific clocks chosen by the integrator. Each userspace client creates a session, providing an enable mask of counter values it requires, a BO for a ring buffer, and a separate BO for the insert and extract indices, along with an eventfd to signal counter capture, all of which are kept fixed for the lifetime of the session. When emitting a sample for a session, counters that were not requested are stripped out, and non-counter information needed to interpret counter values is added to either the sample header, or the block header, which are stored in-line with the counter values in the sample. The proposed uAPI specifies two major sources of supplemental information: - coarse-grained block state transitions are provided on newer FW versions which support the metadata block, a FW-provided counter block which indicates the reason a sample was taken when entering or exiting a non-counting region, or when a shader core has powered down. - the clock assignments to individual blocks is done by integrators, and in order to normalize counter values which count cycles, userspace must know both the clock cycles elapsed over the sampling period, and which of the clocks that particular block is associated with. All of the sessions are then aggregated by the sampler, which handles the programming of the FW interface and subsequent handling of the samples coming from FW. v2: - Fixed offset issues into FW ring buffer - Fixed sparse shader core handling - Added pre- and post- reset handlers - Added module param to control size of FW ring buffer - Clarified naming on sampler functions - Added error logging for PERF_SETUP v3: - Added sample size to the uAPI. - Clarified the bit-to-counter mapping for enable masks. - Fixed IRQ handling: the PERFCNT_THRESHOLD and PERFCNT_OVERFLOW interrupts can be handled by checking the difference between the REQ and ACK bits, whereas PERFCNT_SAMPLE needs external data to validate. - FW ring buffer indices are now only wrapped when reading the buffer and are otherwise left in their pre-wrapped form. - Accumulation index is now bumped after the first copy. - All insert and extract index reads now use the proper, full-width type. - L2 slices are now computed via a macro to extract the relevant bits from the MEM_FEATURES register. This macro was moved from the uAPI due to changes in the register making it unstable. - Consistently take the sampler lock to check if a sample has been requested. [1]: https://lore.kernel.org/lkml/20240305165820.585245-1-adrian.laru...@collabora.com/T/#m67d1f89614fe35dc0560e8304d6731eb1a6942b6 [2]: https://lore.kernel.org/lkml/20241211165024.490748-1-lukas.zapols...@arm.com/ [3]: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35024 Adrián Larumbe (1): drm/panthor: Implement the counter sampler and sample handling Lukas Zapolskas (6): drm/panthor: Add performance counter uAPI drm/panthor: Add DEV_QUERY.PERF_INFO handling for Gx10 drm/panthor: Add panthor perf initialization and termination drm/panthor: Introduce sampling sessions to handle userspace clients drm/panthor: Add suspend, resume and reset handling drm/panthor: Expose the panthor perf ioctls base-commit: 96c85e428ebaeacd2c640eba075479ab92072ccd Adrián Larumbe (1): drm/panthor: Implement the counter sampler and sample handling Lukas Zapolskas (6): drm/panthor: Add performance counter uAPI drm/panthor: Add DEV_QUERY.PERF_INFO handling for Gx10 drm/panthor: Add panthor perf initialization and termination drm/panthor: Introduce sampling sessions to handle userspace clients drm/panthor: Add suspend, resume and reset handling drm/panthor: Expose the panthor perf ioctls drivers/gpu/drm/panthor/Makefile | 1 + drivers/gpu/drm/panthor/panthor_device.c | 14 +- drivers/gpu/drm/panthor/panthor_device.h | 11 +- drivers/gpu/drm/panthor/panthor_drv.c | 150 +- drivers/gpu/drm/panthor/panthor_fw.c | 6 + drivers/gpu/drm/panthor/panthor_fw.h | 9 +- drivers/gpu/drm/panthor/panthor_perf.c | 1982 ++++++++++++++++++++++ drivers/gpu/drm/panthor/panthor_perf.h | 40 + drivers/gpu/drm/panthor/panthor_regs.h | 1 + include/uapi/drm/panthor_drm.h | 565 ++++++ 10 files changed, 2774 insertions(+), 5 deletions(-) create mode 100644 drivers/gpu/drm/panthor/panthor_perf.c create mode 100644 drivers/gpu/drm/panthor/panthor_perf.h base-commit: 96c85e428ebaeacd2c640eba075479ab92072ccd -- 2.33.0.dirty
