drm/xe: Adjust long-running workload timeslices to reasonable values

commit 6f0f404bd289d79a260b634c5b3f4d330b13472c upstream.

A 10ms timeslice for long-running workloads is far too long and causes
significant jitter in benchmarks when the system is shared. Adjust the
value to 5ms for preempt-fencing VMs, as the resume step there is quite
costly as memory is moved around, and set it to zero for pagefault VMs,
since switching back to pagefault mode after dma-fence mode is
relatively fast.

Also change min_run_period_ms to 'unsiged int' type rather than 's64' as
only positive values make sense.

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patch.msgid.link/20251212182847.1683222-2-matthew.brost@intel.com
(cherry picked from commit 33a5abd9a68394aa67f9618b20eee65ee8702ff4)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 79f08337cc270163e7a3fa70493c9d829b3d6ec7..02f2b7ad8a85f0e97ff4e15d847e8eb536fcdfb6 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -1468,7 +1468,10 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
        INIT_WORK(&vm->destroy_work, vm_destroy_work_func);
 
        INIT_LIST_HEAD(&vm->preempt.exec_queues);
-       vm->preempt.min_run_period_ms = 10;     /* FIXME: Wire up to uAPI */
+       if (flags & XE_VM_FLAG_FAULT_MODE)
+               vm->preempt.min_run_period_ms = 0;
+       else
+               vm->preempt.min_run_period_ms = 5;
 
        for_each_tile(tile, xe, id)
                xe_range_fence_tree_init(&vm->rftree[id]);

diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index a4b4091cfd0dab902bc6ad3d26064b50ed9aed67..4f95308a61b8d324a859bfe712b36f8fc107c668 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -243,7 +243,7 @@ struct xe_vm {
                 * @min_run_period_ms: The minimum run period before preempting
                 * an engine again
                 */
-               s64 min_run_period_ms;
+               unsigned int min_run_period_ms;
                /** @exec_queues: list of exec queues attached to this VM */
                struct list_head exec_queues;
                /** @num_exec_queues: number exec queues attached to this VM */