[PATCH 6.12 479/567] drm/xe: Use usleep_range for accurate long-running workload timeslicing

Greg Kroah-Hartman
2026-01-06T17:40:46Z

From: Matthew Brost <matthew.brost@intel.com>

commit 80f9c601d9c4d26f00356c0a9c461650e7089273 upstream.

msleep is not very accurate in terms of how long it actually sleeps,
whereas usleep_range is precise. Replace the timeslice sleep for
long-running workloads with the more accurate usleep_range to avoid
jitter if the sleep period is less than 20ms.

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/20251212182847.1683222-3-matthew.brost@intel.com
(cherry picked from commit ca415c4d4c17ad676a2c8981e1fcc432221dce79)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/xe/xe_guc_submit.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/xe/xe_guc_submit.c
+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
@@ -578,6 +578,24 @@ static u32 wq_space_until_wrap(struct xe
return (WQ_SIZE - q->guc->wqi_tail);
}

+static inline void relaxed_ms_sleep(unsigned int delay_ms)
+{
+ unsigned long min_us, max_us;
+
+ if (!delay_ms)
+ return;
+
+ if (delay_ms > 20) {
+ msleep(delay_ms);
+ return;
+ }
+
+ min_us = mul_u32_u32(delay_ms, 1000);
+ max_us = min_us + 500;
+
+ usleep_range(min_us, max_us);
+}
+
static int wq_wait_for_space(struct xe_exec_queue *q, u32 wqi_size)
{
struct xe_guc *guc = exec_queue_to_guc(q);
@@ -1356,7 +1374,7 @@ static void __guc_exec_queue_process_msg
since_resume_ms;

if (wait_ms > 0 && q->guc->resume_time)
- msleep(wait_ms);
+ relaxed_ms_sleep(wait_ms);

set_exec_queue_suspended(q);
disable_scheduling(q, false);