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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-06-20 15:20:52 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-06-20 16:52:36 +0100 |
| commit | 8ee36e048c98d4015804a23f884be2576f778a93 (patch) | |
| tree | cab87b93f978d11158c3935173858268ca110662 /drivers/gpu/drm/i915/i915_scheduler.c | |
| parent | 22b7a426bbe1ebe1520f92da4cd1617d1e1b5fc4 (diff) | |
| download | lwn-8ee36e048c98d4015804a23f884be2576f778a93.tar.gz lwn-8ee36e048c98d4015804a23f884be2576f778a93.zip | |
drm/i915/execlists: Minimalistic timeslicing
If we have multiple contexts of equal priority pending execution,
activate a timer to demote the currently executing context in favour of
the next in the queue when that timeslice expires. This enforces
fairness between contexts (so long as they allow preemption -- forced
preemption, in the future, will kick those who do not obey) and allows
us to avoid userspace blocking forward progress with e.g. unbounded
MI_SEMAPHORE_WAIT.
For the starting point here, we use the jiffie as our timeslice so that
we should be reasonably efficient wrt frequent CPU wakeups.
Testcase: igt/gem_exec_scheduler/semaphore-resolve
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190620142052.19311-2-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_scheduler.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_scheduler.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c index b1ba3e65cd52..0bd452e851d8 100644 --- a/drivers/gpu/drm/i915/i915_scheduler.c +++ b/drivers/gpu/drm/i915/i915_scheduler.c @@ -394,6 +394,7 @@ bool __i915_sched_node_add_dependency(struct i915_sched_node *node, list_add(&dep->wait_link, &signal->waiters_list); list_add(&dep->signal_link, &node->signalers_list); dep->signaler = signal; + dep->waiter = node; dep->flags = flags; /* Keep track of whether anyone on this chain has a semaphore */ |