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a789761de3
kfd_ioctl_profiler takes a similar approach to that of
kfd_ioctl_dbg_trap (which contains debugger related IOCTL
services) where kfd_ioctl_profiler will contain all profiler
related IOCTL services. The IOCTL is designed to be expanded
as needed to support additional profiler functionality.
The current functionality of the IOCTL is to allow for profilers
which need PMC counters from GPU devices to both signal to other
profilers that may be on the system that the device has active PMC
profiling taking place on it (multiple PMC profilers on the same
device can result in corrupted counter data) and to setup the device
to allow for the collection of SQ PMC data on all queues on the device.
For PMC data for the SQ block (such as SQ_WAVES) to be available
to a profiler, mmPERFCOUNT_ENABLE must be set on the queues. When
profiling a single process, the profiler can inject PM4 packets into
each queue to turn on PERFCOUNT_ENABLE. When profiling system wide,
the profiler does not have this option and must have a way to turn
on profiling for queues in which it cannot inject packets into directly.
Accomplishing this requires a few steps:
1. Checking if the user has the necessary permissions to profile system
wide on the device. This check uses the same check that linux perf
uses to determine if a user has the necessary permissions to profile
at this scope (primarily if the process has CAP_SYS_PERFMON or is root).
2. Locking the device for profiling. This is done by setting a lock bit
on the device struct and storing the process that locked the device.
3. Iterating all queues on the device and issuing an MQD Update to enable
perfcounting on the queues.
4. Actions to cleanup if the process exits or releases the lock.
The IOCTL also contains a link to the existing PC Sampling IOCTL as well.
This is per a suggestion that we should potentially remove the PC Sampling
IOCTL to have it be a part of the profiler IOCTL. This is a future change.
In addition, we do expect to expand the profiler IOCTL to include
additional profiler functionality in the future (which necessitates the
use of a version number).
v2: sqaush in proper IOCTL number
Proposed userpace support:
40abc95a64
Signed-off-by: Benjamin Welton <benjamin.welton@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Acked-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Yifan Zhang <yifan1.zhang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>