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From: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
To: Intel-gfx@lists.freedesktop.org
Subject: [RFC 0/5] LRC irq handler cleanups
Date: Tue, 10 Nov 2015 10:59:40 +0000	[thread overview]
Message-ID: <1447153185-5404-1-git-send-email-tvrtko.ursulin@linux.intel.com> (raw)

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Some random bits to make the LRC irq handler do fewer branching,
locking and VMA lookups per interrupt handled.

I failed to measure a significant gain on a powerful chip but it
definitely results in fewer instructions and branches in the hot
path. So maybe it would help a lower power chip more.

Possibly makes the first run of gem_exec_nop have less variance
eg. branch predictor maybe gets warmed up sooner but I am not
completely confident in this interpretation.

Tvrtko Ursulin (5):
  drm/i915: Avoid invariant conditionals in lrc interrupt handler
  drm/i915: Move LRCA check out of the hot path
  drm/i915: Cache LRCA in the context
  drm/i915: Grab one forcewake across the whole LRC irq handler
  drm/i915: Only grab and calculate timestamps when needed

 drivers/gpu/drm/i915/i915_debugfs.c     |  15 ++--
 drivers/gpu/drm/i915/i915_drv.h         |   1 +
 drivers/gpu/drm/i915/i915_gem.c         |  15 ++--
 drivers/gpu/drm/i915/intel_lrc.c        | 131 +++++++++++++++++++-------------
 drivers/gpu/drm/i915/intel_lrc.h        |   3 +-
 drivers/gpu/drm/i915/intel_ringbuffer.h |   2 +
 6 files changed, 97 insertions(+), 70 deletions(-)

-- 
1.9.1

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             reply	other threads:[~2015-11-10 10:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-10 10:59 Tvrtko Ursulin [this message]
2015-11-10 10:59 ` [PATCH 1/5] drm/i915: Avoid invariant conditionals in lrc interrupt handler Tvrtko Ursulin
2015-11-10 10:59 ` [PATCH 2/5] drm/i915: Move LRCA check out of the hot path Tvrtko Ursulin
2015-11-10 10:59 ` [PATCH 3/5] drm/i915: Cache LRCA in the context Tvrtko Ursulin
2015-11-10 10:59 ` [PATCH 4/5] drm/i915: Grab one forcewake across the whole LRC irq handler Tvrtko Ursulin
2015-11-10 10:59 ` [PATCH 5/5] drm/i915: Only grab and calculate timestamps when needed Tvrtko Ursulin
2015-11-10 11:36 ` [RFC 0/5] LRC irq handler cleanups Chris Wilson
2015-11-10 12:09   ` Tvrtko Ursulin

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