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From: Ben Widawsky <benjamin.widawsky@intel.com>
To: Intel GFX <intel-gfx@lists.freedesktop.org>
Cc: Ben Widawsky <ben@bwidawsk.net>,
	Ben Widawsky <benjamin.widawsky@intel.com>
Subject: [PATCH 06/15] drm/i915: Make semaphore updates more precise
Date: Mon, 16 Dec 2013 20:50:42 -0800	[thread overview]
Message-ID: <1387255851-24824-7-git-send-email-benjamin.widawsky@intel.com> (raw)
In-Reply-To: <1387255851-24824-1-git-send-email-benjamin.widawsky@intel.com>

With the ring mask we now have an easy way to know the number of rings
in the system, and therefore can accurately predict the number of dwords
to emit for semaphore signalling. This was not possible (easily)
previously.

There should be no functional impact, simply fewer instructions emitted.

While we're here, simply do the round up to 2 instead of the fancier
rounding we did before, which rounding up per mbox, ie 4.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 43 +++++++++++++++++----------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 42dbbf8..7a8c5d8 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -635,24 +635,20 @@ static void render_ring_cleanup(struct intel_ring_buffer *ring)
 static int gen6_signal(struct intel_ring_buffer *signaller,
 		       unsigned int num_dwords)
 {
+#define MBOX_UPDATE_DWORDS 4
 	struct drm_device *dev = signaller->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_ring_buffer *useless;
-	int i, ret;
+	int i, ret, num_rings;
 
-	/* NB: In order to be able to do semaphore MBOX updates for varying
-	 * number of rings, it's easiest if we round up each individual update
-	 * to a multiple of 2 (since ring updates must always be a multiple of
-	 * 2) even though the actual update only requires 3 dwords.
-	 */
-#define MBOX_UPDATE_DWORDS 4
-	if (i915_semaphore_is_enabled(dev))
-		num_dwords += ((I915_NUM_RINGS-1) * MBOX_UPDATE_DWORDS);
+	num_rings = hweight_long(INTEL_INFO(dev)->ring_mask);
+	num_dwords = round_up((num_rings-1) * MBOX_UPDATE_DWORDS, 2);
+#undef MBOX_UPDATE_DWORDS
 
-	ret = intel_ring_begin(signaller, num_dwords);
+	/* XXX: + 4 for the caller */
+	ret = intel_ring_begin(signaller, num_dwords + 4);
 	if (ret)
 		return ret;
-#undef MBOX_UPDATE_DWORDS
 
 	for_each_ring(useless, dev_priv, i) {
 		u32 mbox_reg = signaller->semaphore.signal_mbox[i];
@@ -661,14 +657,11 @@ static int gen6_signal(struct intel_ring_buffer *signaller,
 			intel_ring_emit(signaller, mbox_reg);
 			intel_ring_emit(signaller, signaller->outstanding_lazy_seqno);
 			intel_ring_emit(signaller, MI_NOOP);
-		} else {
-			intel_ring_emit(signaller, MI_NOOP);
-			intel_ring_emit(signaller, MI_NOOP);
-			intel_ring_emit(signaller, MI_NOOP);
-			intel_ring_emit(signaller, MI_NOOP);
 		}
 	}
 
+	WARN_ON(i != num_rings);
+
 	return 0;
 }
 
@@ -686,7 +679,11 @@ gen6_add_request(struct intel_ring_buffer *ring)
 {
 	int ret;
 
-	ret = ring->semaphore.signal(ring, 4);
+	if (ring->semaphore.signal)
+		ret = ring->semaphore.signal(ring, 4);
+	else
+		ret = intel_ring_begin(ring, 4);
+
 	if (ret)
 		return ret;
 
@@ -1877,7 +1874,8 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 		ring->get_seqno = gen6_ring_get_seqno;
 		ring->set_seqno = ring_set_seqno;
 		ring->semaphore.sync_to = gen6_ring_sync;
-		ring->semaphore.signal = gen6_signal;
+		if (i915_semaphore_is_enabled(dev))
+			ring->semaphore.signal = gen6_signal;
 		ring->semaphore.mbox[RCS] = MI_SEMAPHORE_SYNC_INVALID;
 		ring->semaphore.mbox[VCS] = MI_SEMAPHORE_SYNC_RV;
 		ring->semaphore.mbox[BCS] = MI_SEMAPHORE_SYNC_RB;
@@ -2054,7 +2052,8 @@ int intel_init_bsd_ring_buffer(struct drm_device *dev)
 				gen6_ring_dispatch_execbuffer;
 		}
 		ring->semaphore.sync_to = gen6_ring_sync;
-		ring->semaphore.signal = gen6_signal;
+		if (i915_semaphore_is_enabled(dev))
+			ring->semaphore.signal = gen6_signal;
 		ring->semaphore.mbox[RCS] = MI_SEMAPHORE_SYNC_VR;
 		ring->semaphore.mbox[VCS] = MI_SEMAPHORE_SYNC_INVALID;
 		ring->semaphore.mbox[BCS] = MI_SEMAPHORE_SYNC_VB;
@@ -2112,7 +2111,8 @@ int intel_init_blt_ring_buffer(struct drm_device *dev)
 		ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
 	}
 	ring->semaphore.sync_to = gen6_ring_sync;
-	ring->semaphore.signal = gen6_signal;
+	if (i915_semaphore_is_enabled(dev))
+		ring->semaphore.signal = gen6_signal;
 	ring->semaphore.mbox[RCS] = MI_SEMAPHORE_SYNC_BR;
 	ring->semaphore.mbox[VCS] = MI_SEMAPHORE_SYNC_BV;
 	ring->semaphore.mbox[BCS] = MI_SEMAPHORE_SYNC_INVALID;
@@ -2154,7 +2154,8 @@ int intel_init_vebox_ring_buffer(struct drm_device *dev)
 		ring->dispatch_execbuffer = gen6_ring_dispatch_execbuffer;
 	}
 	ring->semaphore.sync_to = gen6_ring_sync;
-	ring->semaphore.signal = gen6_signal;
+	if (i915_semaphore_is_enabled(dev))
+		ring->semaphore.signal = gen6_signal;
 	ring->semaphore.mbox[RCS] = MI_SEMAPHORE_SYNC_VER;
 	ring->semaphore.mbox[VCS] = MI_SEMAPHORE_SYNC_VEV;
 	ring->semaphore.mbox[BCS] = MI_SEMAPHORE_SYNC_VEB;
-- 
1.8.5.1

  parent reply	other threads:[~2013-12-17  4:51 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-17  4:50 [PATCH 00/15] [v2] Broadwell HW semaphore Ben Widawsky
2013-12-17  4:50 ` [PATCH 01/15] drm/i915: Reorder/respace MI instruction definition Ben Widawsky
2013-12-17 23:06   ` [PATCH 01.5/15] drm/i915: Make semaphore modparam RO Ben Widawsky
2013-12-17  4:50 ` [PATCH 02/15] drm/i915: Don't emit mbox updates without semaphores Ben Widawsky
2013-12-17 19:24   ` Chris Wilson
2013-12-17 22:02     ` Ben Widawsky
2013-12-17 22:47       ` Chris Wilson
2013-12-17  4:50 ` [PATCH 03/15] drm/i915: Move semaphore specific ring members to struct Ben Widawsky
2013-12-17  4:50 ` [PATCH 04/15] drm/i915: Virtualize the ringbuffer signal func Ben Widawsky
2013-12-17  4:50 ` [PATCH 05/15] drm/i915: Move ring_begin to signal() Ben Widawsky
2013-12-17  4:50 ` Ben Widawsky [this message]
2013-12-17  9:49   ` [PATCH 06/15] drm/i915: Make semaphore updates more precise Chris Wilson
2013-12-17  4:50 ` [PATCH 07/15] drm/i915: gen specific ring init Ben Widawsky
2013-12-17  8:52   ` Daniel Vetter
2013-12-17  4:50 ` [PATCH 08/15] drm/i915/bdw: implement semaphore signal Ben Widawsky
2013-12-17 19:11   ` Chris Wilson
2013-12-17 23:00     ` [PATCH 08/15] [v3] " Ben Widawsky
2013-12-17  4:50 ` [PATCH 09/15] drm/i915/bdw: implement semaphore wait Ben Widawsky
2013-12-17 19:22   ` Chris Wilson
2013-12-17 23:31     ` [PATCH 09/15] [v3] " Ben Widawsky
2013-12-17  4:50 ` [PATCH 10/15] drm/i915: FORCE_RESTORE for gen8 semaphores Ben Widawsky
2013-12-17  4:50 ` [PATCH 11/15] drm/i915/bdw: poll semaphores Ben Widawsky
2013-12-17 19:17   ` Chris Wilson
2013-12-17  4:50 ` [PATCH 12/15] drm/i915: Extract semaphore error collection Ben Widawsky
2013-12-17 19:14   ` Chris Wilson
2013-12-17 23:37     ` Ben Widawsky
2013-12-17  4:50 ` [PATCH 13/15] drm/i915/bdw: collect semaphore error state Ben Widawsky
2013-12-17  4:50 ` [PATCH 14/15] drm/i915: unleash semaphores on gen8 Ben Widawsky
2013-12-17  4:50 ` [PATCH 15/15] drm/i915: semaphore debugfs Ben Widawsky
2013-12-17  9:17 ` [PATCH 00/15] [v2] Broadwell HW semaphore Daniel Vetter
2013-12-17 16:29   ` Damien Lespiau
2013-12-17 18:21     ` Daniel Vetter

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