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[Qemu-devel] [5839] qemu-img: open files with cache=writeback
From: |
Aurelien Jarno |
Subject: |
[Qemu-devel] [5839] qemu-img: open files with cache=writeback |
Date: |
Sun, 30 Nov 2008 19:12:50 +0000 |
Revision: 5839
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5839
Author: aurel32
Date: 2008-11-30 19:12:49 +0000 (Sun, 30 Nov 2008)
Log Message:
-----------
qemu-img: open files with cache=writeback
Data integrity is not important in qemu-img, so open the files with
cache=writeback. This fixes the performance regression seen with qemu-img
since revision 5485, and most particularly with the qcow2 format.
Signed-off-by: Aurelien Jarno <address@hidden>
Revision Links:
--------------
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5485
Modified Paths:
--------------
trunk/qemu-img.c
Modified: trunk/qemu-img.c
===================================================================
--- trunk/qemu-img.c 2008-11-30 17:54:28 UTC (rev 5838)
+++ trunk/qemu-img.c 2008-11-30 19:12:49 UTC (rev 5839)
@@ -30,6 +30,9 @@
#include <windows.h>
#endif
+/* Default to cache=writeback as data integrity is not important for qemu-tcg.
*/
+#define BRDV_O_FLAGS BDRV_O_CACHE_WB
+
static void __attribute__((noreturn)) error(const char *fmt, ...)
{
va_list ap;
@@ -186,7 +189,7 @@
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, 0, drv) < 0) {
+ if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
error("Could not open '%s'", filename);
}
if (bdrv_is_encrypted(bs)) {
@@ -317,7 +320,7 @@
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, 0, drv) < 0) {
+ if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
error("Could not open '%s'", filename);
}
ret = bdrv_commit(bs);
@@ -691,7 +694,7 @@
} else {
drv = NULL;
}
- if (bdrv_open2(bs, filename, 0, drv) < 0) {
+ if (bdrv_open2(bs, filename, BRDV_O_FLAGS, drv) < 0) {
error("Could not open '%s'", filename);
}
bdrv_get_format(bs, fmt_name, sizeof(fmt_name));
- [Qemu-devel] [5839] qemu-img: open files with cache=writeback,
Aurelien Jarno <=