Hi,
Attached are two small patches which eliminate some tight malloc/free
cycles while servicing common XRender requests. This goes in
conjunction with overhead-reduction and fastpath patches already
submitted to Pixman.
Since even good malloc implementations have significant overhead, this
improves throughput for small requests in particular. We've seen about
20% on ARMv7-A hardware, over and above the improvement from running an
optimised Pixman library.
Note that the simple object-pools implemented here are not thread-safe.
As I understand it, thread-safety is not a requirement for X.org.
Please do correct me if necessary.
A further, rather heavier patch is necessary to eliminate all
malloc/free cycles from RenderGlyphs calls, which results in
considerable further improvements in glyph-request throughput. I'll
post that when I'm happier with it, since it involves major surgery to
miGlyphs().
--
------
From: Jonathan Morton
[email protected]
>From 9a34e056a1018014927a316307b1cf543da68357 Mon Sep 17 00:00:00 2001
From: Jonathan Morton <[email protected]>
Date: Mon, 8 Jun 2009 12:17:24 +0300
Subject: [PATCH] Introduce region-object pool to avoid malloc/free overhead.
---
mi/miregion.c | 22 ++++++++++++++++++----
1 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/mi/miregion.c b/mi/miregion.c
index c48befc..a352cc6 100644
--- a/mi/miregion.c
+++ b/mi/miregion.c
@@ -224,6 +224,11 @@ RegDataRec miEmptyData = {0, 0};
RegDataRec miBrokenData = {0, 0};
static RegionRec miBrokenRegion = { { 0, 0, 0, 0 }, &miBrokenData };
+/* Avoid calling malloc every time one of these is needed */
+#define REGION_POOL_SIZE (4)
+static RegionPtr miRegionPool[REGION_POOL_SIZE] = {NULL};
+static uint32_t miRegionPoolTop = 0;
+
void
InitRegions (void)
{
@@ -239,9 +244,13 @@ InitRegions (void)
RegionPtr
miRegionCreate(BoxPtr rect, int size)
{
- RegionPtr pReg;
+ RegionPtr pReg = NULL;
- pReg = (RegionPtr)xalloc(sizeof(RegionRec));
+ if(miRegionPoolTop)
+ pReg = miRegionPool[--miRegionPoolTop];
+ else
+ pReg = (RegionPtr)xalloc(sizeof(RegionRec));
+
if (!pReg)
return &miBrokenRegion;
@@ -254,8 +263,13 @@ void
miRegionDestroy(RegionPtr pReg)
{
pixman_region_fini (pReg);
- if (pReg != &miBrokenRegion)
- xfree(pReg);
+
+ if (pReg != &miBrokenRegion) {
+ if(miRegionPoolTop < REGION_POOL_SIZE)
+ miRegionPool[miRegionPoolTop++] = pReg;
+ else
+ xfree(pReg);
+ }
}
void
--
1.5.6.3
>From ff0224fe256ebc0726ffda27e4a93dc09f4e3bb2 Mon Sep 17 00:00:00 2001
From: Jonathan Morton <[email protected]>
Date: Mon, 8 Jun 2009 12:18:02 +0300
Subject: [PATCH] Introduce picture-object pool to avoid malloc/free overhead.
---
render/picture.c | 17 +++++++++++++++--
1 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/render/picture.c b/render/picture.c
index 5f86c7c..c94add0 100644
--- a/render/picture.c
+++ b/render/picture.c
@@ -703,6 +703,11 @@ SetPictureToDefaults (PicturePtr pPicture)
pPicture->pSourcePict = 0;
}
+/* Avoid calling malloc every time one of these is needed */
+#define PICTURE_POOL_SIZE (4)
+static PicturePtr PicturePool[PICTURE_POOL_SIZE] = {NULL};
+static uint32_t PicturePoolTop = 0;
+
PicturePtr
CreatePicture (Picture pid,
DrawablePtr pDrawable,
@@ -715,7 +720,11 @@ CreatePicture (Picture pid,
PicturePtr pPicture;
PictureScreenPtr ps = GetPictureScreen(pDrawable->pScreen);
- pPicture = (PicturePtr)xalloc(sizeof(PictureRec));
+ if(PicturePoolTop)
+ pPicture = PicturePool[--PicturePoolTop];
+ else
+ pPicture = (PicturePtr)xalloc(sizeof(PictureRec));
+
if (!pPicture)
{
*error = BadAlloc;
@@ -1531,7 +1540,11 @@ FreePicture (pointer value,
}
}
dixFreePrivates(pPicture->devPrivates);
- xfree (pPicture);
+
+ if(PicturePoolTop < PICTURE_POOL_SIZE)
+ PicturePool[PicturePoolTop++] = pPicture;
+ else
+ xfree (pPicture);
}
return Success;
}
--
1.5.6.3
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