diff options
| -rw-r--r-- | block.h | 3 | ||||
| -rw-r--r-- | block/qcow2.c | 8 | ||||
| -rw-r--r-- | qemu-options.hx | 4 | ||||
| -rw-r--r-- | vl.c | 4 |
4 files changed, 3 insertions, 16 deletions
@@ -37,9 +37,8 @@ typedef struct QEMUSnapshotInfo { bdrv_file_open()) */ #define BDRV_O_NOCACHE 0x0020 /* do not use the host page cache */ #define BDRV_O_CACHE_WB 0x0040 /* use write-back caching */ -#define BDRV_O_CACHE_DEF 0x0080 /* use default caching */ -#define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_CACHE_DEF) +#define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_CACHE_WB) void bdrv_info(Monitor *mon); void bdrv_info_stats(Monitor *mon); diff --git a/block/qcow2.c b/block/qcow2.c index 20c114b139..9a7c666ee7 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -145,14 +145,6 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) QCowHeader header; uint64_t ext_end; - /* Performance is terrible right now with cache=writethrough due mainly - * to reference count updates. If the user does not explicitly specify - * a caching type, force to writeback caching. - */ - if ((flags & BDRV_O_CACHE_DEF)) { - flags |= BDRV_O_CACHE_WB; - flags &= ~BDRV_O_CACHE_DEF; - } ret = bdrv_file_open(&s->hd, filename, flags); if (ret < 0) return ret; diff --git a/qemu-options.hx b/qemu-options.hx index 8947d05393..cadc82293b 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -148,9 +148,7 @@ an internal copy of the data. Some block drivers perform badly with @option{cache=writethrough}, most notably, qcow2. If performance is more important than correctness, -@option{cache=writeback} should be used with qcow2. By default, if no explicit -caching is specified for a qcow2 disk image, @option{cache=writeback} will be -used. For all other disk types, @option{cache=writethrough} is the default. +@option{cache=writeback} should be used with qcow2. Instead of @option{-cdrom} you can use: @example @@ -2239,7 +2239,7 @@ int drive_init(struct drive_opt *arg, int snapshot, void *opaque) unit_id = -1; translation = BIOS_ATA_TRANSLATION_AUTO; index = -1; - cache = 3; + cache = 1; if (machine->use_scsi) { type = IF_SCSI; @@ -2557,8 +2557,6 @@ int drive_init(struct drive_opt *arg, int snapshot, void *opaque) bdrv_flags |= BDRV_O_NOCACHE; else if (cache == 2) /* write-back */ bdrv_flags |= BDRV_O_CACHE_WB; - else if (cache == 3) /* not specified */ - bdrv_flags |= BDRV_O_CACHE_DEF; if (bdrv_open2(bdrv, file, bdrv_flags, drv) < 0) { fprintf(stderr, "qemu: could not open disk image %s\n", file); |