| Message ID | 1302368879-6070-1-git-send-email-levinsasha928@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Apr 9, 2011 at 8:07 PM, Sasha Levin <levinsasha928@gmail.com> wrote: > Now openning map with MAP_SHARED. > > Attempt to use mmap first for working with a disk image, if the attempt is failed (for example, large image on a 32bit system) fallback to using read/write. > > Performance (kB/s) test using bonnie++ showed the following improvement: > > kvm cmdline: ./kvm run --mem=256 --image=./work/vms/gentoo.img --kernel=/boot/bzImage-git > bonnie++ cmdline: bonnie++ -u 0 > > Before: > Version 1.96 ------Sequential Output----- --Sequential Input- -Random- > Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP > tux 480M 673 100 308017 61 288156 49 3286 99 892186 76 +++++ +++ > Latency 12998us 50992us 35993us 3000us 1999us 201ms > Version 1.96 ------Sequential Create------ --------Random Create-------- > tux -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- > files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP > 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ > Latency 3000us 1000us 1000us 1000us 1998us 1000us > > Version 1.96 ------Sequential Output------ --Sequential Input- --Random- > Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP > tux 480M 674 99 366588 42 309514 44 3539 99 954554 76 +++++ +++ > Latency 17997us 15997us 37993us 4999us 1998us 145ms > Version 1.96 ------Sequential Create------ --------Random Create-------- > tux -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- > files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP > 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ > Latency 1000us 1000us 2000us 1999us 1000us 1000us > > Signed-off-by: Sasha Levin <levinsasha928@gmail.com> I applied this because throughput improves. I need to revisit the decision after we fix the blocking I/O model. > +struct disk_image *disk_image__new(int fd, uint64_t size) > +{ > + struct disk_image *self; > + > + self = malloc(sizeof *self); > + if (!self) > + return NULL; > + > + self->fd = fd; > + self->size = size; > + self->priv = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_NORESERVE, fd, 0); Btw, I dropped MAP_NORESERVE. It's a no-op with MAP_SHARED. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/tools/kvm/disk-image.c b/tools/kvm/disk-image.c index 9deaf45..5b2647b 100644 --- a/tools/kvm/disk-image.c +++ b/tools/kvm/disk-image.c @@ -13,21 +13,31 @@ #include <unistd.h> #include <fcntl.h> -struct disk_image *disk_image__new(int fd, uint64_t size, struct disk_image_operations *ops) +static int raw_image__read_sector_mmap(struct disk_image *self, uint64_t sector, void *dst, uint32_t dst_len) { - struct disk_image *self; + uint64_t offset = sector << SECTOR_SHIFT; - self = malloc(sizeof *self); - if (!self) - return NULL; + if (offset + dst_len > self->size) + return -1; - self->fd = fd; - self->size = size; - self->ops = ops; + memcpy(dst, self->priv + offset, dst_len); - return self; + return 0; } +static int raw_image__write_sector_mmap(struct disk_image *self, uint64_t sector, void *src, uint32_t src_len) +{ + uint64_t offset = sector << SECTOR_SHIFT; + + if (offset + src_len > self->size) + return -1; + + memcpy(self->priv + offset, src, src_len); + + return 0; +} + + static int raw_image__read_sector(struct disk_image *self, uint64_t sector, void *dst, uint32_t dst_len) { uint64_t offset = sector << SECTOR_SHIFT; @@ -59,6 +69,27 @@ static struct disk_image_operations raw_image_ops = { .write_sector = raw_image__write_sector, }; +static struct disk_image_operations raw_image_mmap_ops = { + .read_sector = raw_image__read_sector_mmap, + .write_sector = raw_image__write_sector_mmap, +}; + +struct disk_image *disk_image__new(int fd, uint64_t size) +{ + struct disk_image *self; + + self = malloc(sizeof *self); + if (!self) + return NULL; + + self->fd = fd; + self->size = size; + self->priv = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_NORESERVE, fd, 0); + self->ops = (self->priv == MAP_FAILED) ? &raw_image_ops : &raw_image_mmap_ops; + + return self; +} + static struct disk_image *raw_image__probe(int fd) { struct stat st; @@ -66,7 +97,7 @@ static struct disk_image *raw_image__probe(int fd) if (fstat(fd, &st) < 0) return NULL; - return disk_image__new(fd, st.st_size, &raw_image_ops); + return disk_image__new(fd, st.st_size); } struct disk_image *disk_image__open(const char *filename) @@ -97,6 +128,9 @@ void disk_image__close(struct disk_image *self) if (self->ops->close) self->ops->close(self); + if (self->priv != MAP_FAILED) + munmap(self->priv, self->size); + if (close(self->fd) < 0) warning("close() failed"); diff --git a/tools/kvm/include/kvm/disk-image.h b/tools/kvm/include/kvm/disk-image.h index df0a15d..8b78657 100644 --- a/tools/kvm/include/kvm/disk-image.h +++ b/tools/kvm/include/kvm/disk-image.h @@ -22,7 +22,7 @@ struct disk_image { }; struct disk_image *disk_image__open(const char *filename); -struct disk_image *disk_image__new(int fd, uint64_t size, struct disk_image_operations *ops); +struct disk_image *disk_image__new(int fd, uint64_t size); void disk_image__close(struct disk_image *self); static inline int disk_image__read_sector(struct disk_image *self, uint64_t sector, void *dst, uint32_t dst_len)
Now openning map with MAP_SHARED. Attempt to use mmap first for working with a disk image, if the attempt is failed (for example, large image on a 32bit system) fallback to using read/write. Performance (kB/s) test using bonnie++ showed the following improvement: kvm cmdline: ./kvm run --mem=256 --image=./work/vms/gentoo.img --kernel=/boot/bzImage-git bonnie++ cmdline: bonnie++ -u 0 Before: Version 1.96 ------Sequential Output----- --Sequential Input- -Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP tux 480M 673 100 308017 61 288156 49 3286 99 892186 76 +++++ +++ Latency 12998us 50992us 35993us 3000us 1999us 201ms Version 1.96 ------Sequential Create------ --------Random Create-------- tux -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ Latency 3000us 1000us 1000us 1000us 1998us 1000us Version 1.96 ------Sequential Output------ --Sequential Input- --Random- Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP tux 480M 674 99 366588 42 309514 44 3539 99 954554 76 +++++ +++ Latency 17997us 15997us 37993us 4999us 1998us 145ms Version 1.96 ------Sequential Create------ --------Random Create-------- tux -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ Latency 1000us 1000us 2000us 1999us 1000us 1000us Signed-off-by: Sasha Levin <levinsasha928@gmail.com> --- tools/kvm/disk-image.c | 54 +++++++++++++++++++++++++++++------ tools/kvm/include/kvm/disk-image.h | 2 +- 2 files changed, 45 insertions(+), 11 deletions(-)