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authorFredrik Höglund <fredrik@kde.org>2008-03-31 21:15:50 +0200
committerFredrik Höglund <fredrik@kde.org>2008-03-31 21:15:50 +0200
commit93d876891dbba41b920a9a29a5de77f647f43928 (patch)
tree62191a3b791723bc326b9a323356884e4c77b8bb
parent7034484f0887ea0f8ab956515f2d9301ea5842ce (diff)
EXA: Improve the algorithm used for tracking offscreen pixmap use.
Replace the current score keeping algorithm with a rolling counter that's incremented in ExaOffscreenMarkUsed, with the previous value being stored in the area. exaOffscreenAlloc uses the difference between the counter value and the value in the area when deciding which area to evict. It now also takes the size of the areas into account, and favors evicting smaller areas. The credit for these ideas goes to Michel Dänzer.
-rw-r--r--exa/exa.h2
-rw-r--r--exa/exa_offscreen.c36
-rw-r--r--exa/exa_priv.h1
3 files changed, 16 insertions, 23 deletions
diff --git a/exa/exa.h b/exa/exa.h
index 0774a700a..97ae6c0a5 100644
--- a/exa/exa.h
+++ b/exa/exa.h
@@ -56,7 +56,7 @@ struct _ExaOffscreenArea {
int base_offset; /* allocation base */
int offset; /* aligned offset */
int size; /* total allocation size */
- int score;
+ unsigned last_use;
pointer privData;
ExaOffscreenSaveProc save;
diff --git a/exa/exa_offscreen.c b/exa/exa_offscreen.c
index c666b001b..2701e84cf 100644
--- a/exa/exa_offscreen.c
+++ b/exa/exa_offscreen.c
@@ -71,6 +71,8 @@ ExaOffscreenKickOut (ScreenPtr pScreen, ExaOffscreenArea *area)
return exaOffscreenFree (pScreen, area);
}
+#define AREA_SCORE(area) (area->size / (double)(pExaScr->offScreenCounter - area->last_use))
+
/**
* exaOffscreenAlloc allocates offscreen memory
*
@@ -98,7 +100,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
{
ExaOffscreenArea *area, *begin, *best;
ExaScreenPriv (pScreen);
- int tmp, real_size = 0, best_score;
+ int tmp, real_size = 0;
#if DEBUG_OFFSCREEN
static int number = 0;
ErrorF("================= ============ allocating a new pixmap %d\n", ++number);
@@ -143,6 +145,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
if (!area)
{
+ double best_score;
/*
* Kick out existing users to make space.
*
@@ -151,11 +154,12 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
/* prev points at the first object to boot */
best = NULL;
- best_score = INT_MAX;
+ best_score = UINT_MAX;
for (begin = pExaScr->info->offScreenAreas; begin != NULL;
begin = begin->next)
{
- int avail, score;
+ int avail;
+ double score;
ExaOffscreenArea *scan;
if (begin->state == ExaOffscreenLocked)
@@ -177,8 +181,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
begin = scan;
break;
}
- /* Score should only be non-zero for ExaOffscreenRemovable */
- score += scan->score;
+ score += AREA_SCORE(scan);
avail += scan->size;
if (avail >= real_size)
break;
@@ -230,7 +233,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
new_area->size = area->size - real_size;
new_area->state = ExaOffscreenAvail;
new_area->save = NULL;
- new_area->score = 0;
+ new_area->last_use = 0;
new_area->next = area->next;
area->next = new_area;
area->size = real_size;
@@ -244,7 +247,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
area->state = ExaOffscreenRemovable;
area->privData = privData;
area->save = save;
- area->score = 0;
+ area->last_use = pExaScr->offScreenCounter++;
area->offset = (area->base_offset + align - 1);
area->offset -= area->offset % align;
@@ -395,7 +398,7 @@ exaOffscreenFree (ScreenPtr pScreen, ExaOffscreenArea *area)
area->state = ExaOffscreenAvail;
area->save = NULL;
- area->score = 0;
+ area->last_use = 0;
/*
* Find previous area
*/
@@ -427,23 +430,11 @@ ExaOffscreenMarkUsed (PixmapPtr pPixmap)
{
ExaPixmapPriv (pPixmap);
ExaScreenPriv (pPixmap->drawable.pScreen);
- static int iter = 0;
if (!pExaPixmap || !pExaPixmap->area)
return;
- /* The numbers here are arbitrary. We may want to tune these. */
- pExaPixmap->area->score += 100;
- if (++iter == 10) {
- ExaOffscreenArea *area;
- for (area = pExaScr->info->offScreenAreas; area != NULL;
- area = area->next)
- {
- if (area->state == ExaOffscreenRemovable)
- area->score = (area->score * 7) / 8;
- }
- iter = 0;
- }
+ pExaPixmap->area->last_use = pExaScr->offScreenCounter++;
}
/**
@@ -472,10 +463,11 @@ exaOffscreenInit (ScreenPtr pScreen)
area->size = pExaScr->info->memorySize - area->base_offset;
area->save = NULL;
area->next = NULL;
- area->score = 0;
+ area->last_use = 0;
/* Add it to the free areas */
pExaScr->info->offScreenAreas = area;
+ pExaScr->offScreenCounter = 1;
ExaOffscreenValidate (pScreen);
diff --git a/exa/exa_priv.h b/exa/exa_priv.h
index 89f47184f..e41f46aba 100644
--- a/exa/exa_priv.h
+++ b/exa/exa_priv.h
@@ -120,6 +120,7 @@ typedef struct {
Bool checkDirtyCorrectness;
unsigned disableFbCount;
Bool optimize_migration;
+ unsigned offScreenCounter;
} ExaScreenPrivRec, *ExaScreenPrivPtr;
/*