diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-07-01 17:23:16 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2016-07-01 20:58:47 +0100 |
| commit | f69a02c9d57d50c7f688cf0be2b65ea9e3087fc9 (patch) | |
| tree | 75fc4176cb9b5ebd58afa69703ece991a6a04e86 /drivers/gpu/drm/i915/i915_debugfs.c | |
| parent | 688e6c7258164de86d626e8e983ca8d28015c263 (diff) | |
drm/i915: Spin after waking up for an interrupt
When waiting for an interrupt (waiting for the engine to complete some
work), we know we are the only waiter to be woken on this engine. We also
know when the GPU has nearly completed our request (or at least started
processing it), so after being woken and we detect that the GPU is
active and working on our request, allow us the bottom-half (the first
waiter who wakes up to handle checking the seqno after the interrupt) to
spin for a very short while to reduce client latencies.
The impact is minimal, there was an improvement to the realtime-vs-many
clients case, but exporting the function proves useful later. However,
it is tempting to adjust irq_seqno_barrier to include the spin. The
problem is first ensuring that the "start-of-request" seqno is coherent
as we use that as our basis for judging when it is ok to spin. If we
could, spinning there could dramatically shorten some sleeps, and allow
us to make the barriers more conservative to handle missed seqno writes
on more platforms (all gen7+ are known to have the occasional issue, at
least).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467390209-3576-7-git-send-email-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_debugfs.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_debugfs.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index f522a366223d..309bb2f1a1e8 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -663,7 +663,7 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data) i915_gem_request_get_seqno(work->flip_queued_req), dev_priv->next_seqno, engine->get_seqno(engine), - i915_gem_request_completed(work->flip_queued_req, true)); + i915_gem_request_completed(work->flip_queued_req)); } else seq_printf(m, "Flip not associated with any ring\n"); seq_printf(m, "Flip queued on frame %d, (was ready on frame %d), now %d\n", |