On 12/15/2011 08:15 PM, Sasha Levin wrote: > When using AIO, submit all requests which exists in the vring in a single > io_submit instead of one io_submit for each descriptor. > > Benchmarks: > > Short version: 15%+ increase in IOPS, small increase in BW. > > Read IOPS: > Before: > vda: ios=291792/0, merge=0/0, ticks=35229/0, in_queue=31025, util=61.30%
I guess you are reading the wrong IOPS number, the 'ios' is the number of ios performed by all groups, not the IOPS result. Find the 'iops' ;-) So, Here is the number without/with this patch. (seq-read, seq-write, rand-read, rand-write) Before: read : io=98304KB, bw=63015KB/s, iops=15753, runt= 1560msec write: io=98304KB, bw=56823KB/s, iops=14205, runt= 1730msec read : io=98304KB, bw=62139KB/s, iops=15534, runt= 1582msec write: io=98304KB, bw=53836KB/s, iops=13458, runt= 1826msec After: read : io=98304KB, bw=63096KB/s, iops=15774, runt= 1558msec write: io=98304KB, bw=55823KB/s, iops=13955, runt= 1761msec read : io=98304KB, bw=59148KB/s, iops=14787, runt= 1662msec write: io=98304KB, bw=55072KB/s, iops=13768, runt= 1785msec Submit more io requests in one time is not supposed to increase the iops or bw so dramatically. I even tried to submit all read/write ops in one io_submit which still ends up with very little iops or bw improvement. > > After: > vda: ios=333114/0, merge=0/0, ticks=47983/0, in_queue=46630, util=62.22% > > Write IOPS: > Before: > vda: ios=0/271716, merge=0/0, ticks=0/33367, in_queue=26531, util=59.96% > > After: > vda: ios=0/327485, merge=0/0, ticks=0/23789, in_queue=22475, util=55.74% > > Read BW: > Before: > READ: io=7526.0MB, aggrb=1246.3MB/s, minb=1275.1MB/s, maxb=1275.1MB/s, > mint=6040msec, maxt=6040msec > After: > READ: io=7526.0MB, aggrb=1315.5MB/s, minb=1346.7MB/s, maxb=1346.7MB/s, > mint=5723msec, maxt=5723msec > > Write BW: > Before: > WRITE: io=7526.0MB, aggrb=1110.2MB/s, minb=1136.9MB/s, maxb=1136.9MB/s, > mint=6779msec, maxt=6779msec > > After: > WRITE: io=7526.0MB, aggrb=1113.5MB/s, minb=1140.3MB/s, maxb=1140.3MB/s, > mint=6759msec, maxt=6759msec > > Signed-off-by: Sasha Levin <[email protected]> > --- > tools/kvm/disk/core.c | 2 - > tools/kvm/disk/raw.c | 38 +++++++++++++++++++++++++++++------ > tools/kvm/include/kvm/disk-image.h | 8 +++++- > tools/kvm/util/read-write.c | 8 +----- > tools/kvm/virtio/blk.c | 3 ++ > 5 files changed, 42 insertions(+), 17 deletions(-) > > diff --git a/tools/kvm/disk/core.c b/tools/kvm/disk/core.c > index 4915efd..b18014e 100644 > --- a/tools/kvm/disk/core.c > +++ b/tools/kvm/disk/core.c > @@ -5,8 +5,6 @@ > #include <sys/eventfd.h> > #include <sys/poll.h> > > -#define AIO_MAX 32 > - > int debug_iodelay; > > #ifdef CONFIG_HAS_AIO > diff --git a/tools/kvm/disk/raw.c b/tools/kvm/disk/raw.c > index caa023c..1162fb7 100644 > --- a/tools/kvm/disk/raw.c > +++ b/tools/kvm/disk/raw.c > @@ -10,9 +10,9 @@ ssize_t raw_image__read_sector(struct disk_image *disk, u64 > sector, const struct > u64 offset = sector << SECTOR_SHIFT; > > #ifdef CONFIG_HAS_AIO > - struct iocb iocb; > + struct iocb *iocb = &disk->iocb[disk->count++]; > > - return aio_preadv(disk->ctx, &iocb, disk->fd, iov, iovcount, offset, > + return aio_preadv(disk->ctx, iocb, disk->fd, iov, iovcount, offset, > disk->evt, param); > #else > return preadv_in_full(disk->fd, iov, iovcount, offset); > @@ -25,9 +25,9 @@ ssize_t raw_image__write_sector(struct disk_image *disk, > u64 sector, const struc > u64 offset = sector << SECTOR_SHIFT; > > #ifdef CONFIG_HAS_AIO > - struct iocb iocb; > + struct iocb *iocb = &disk->iocb[disk->count++]; > > - return aio_pwritev(disk->ctx, &iocb, disk->fd, iov, iovcount, offset, > + return aio_pwritev(disk->ctx, iocb, disk->fd, iov, iovcount, offset, > disk->evt, param); > #else > return pwritev_in_full(disk->fd, iov, iovcount, offset); > @@ -79,19 +79,33 @@ int raw_image__close(struct disk_image *disk) > > close(disk->evt); > > -#ifdef CONFIG_HAS_VIRTIO > +#ifdef CONFIG_HAS_AIO > io_destroy(disk->ctx); > #endif > > return ret; > } > > +static int raw_image__aio_submit(struct disk_image *disk) > +{ > + int ret; > + > + ret = io_submit(disk->ctx, disk->count, disk->iocb_ptrs); > + if (ret > 0) > + disk->count = 0; > + > + return ret; > +} > + > /* > * multiple buffer based disk image operations > */ > static struct disk_image_operations raw_image_regular_ops = { > .read_sector = raw_image__read_sector, > .write_sector = raw_image__write_sector, > +#ifdef CONFIG_HAS_AIO > + .submit = raw_image__aio_submit, > +#endif > }; > > struct disk_image_operations ro_ops = { > @@ -120,8 +134,13 @@ struct disk_image *raw_image__probe(int fd, struct stat > *st, bool readonly) > > disk = disk_image__new(fd, st->st_size, > &ro_ops_nowrite, DISK_IMAGE_REGULAR); > #ifdef CONFIG_HAS_AIO > - if (disk) > + if (disk) { > + int i; > + > disk->async = 1; > + for (i = 0; i < AIO_MAX; i++) > + disk->iocb_ptrs[i] = &disk->iocb[i]; > + } > #endif > } > > @@ -132,8 +151,13 @@ struct disk_image *raw_image__probe(int fd, struct stat > *st, bool readonly) > */ > disk = disk_image__new(fd, st->st_size, &raw_image_regular_ops, > DISK_IMAGE_REGULAR); > #ifdef CONFIG_HAS_AIO > - if (disk) > + if (disk) { > + int i; > + > disk->async = 1; > + for (i = 0; i < AIO_MAX; i++) > + disk->iocb_ptrs[i] = &disk->iocb[i]; > + } > #endif > return disk; > } > diff --git a/tools/kvm/include/kvm/disk-image.h > b/tools/kvm/include/kvm/disk-image.h > index 56c08da..6eba950 100644 > --- a/tools/kvm/include/kvm/disk-image.h > +++ b/tools/kvm/include/kvm/disk-image.h > @@ -20,14 +20,14 @@ > > #define SECTOR_SHIFT 9 > #define SECTOR_SIZE (1UL << SECTOR_SHIFT) > +#define AIO_MAX 256 > +#define MAX_DISK_IMAGES 4 > > enum { > DISK_IMAGE_REGULAR, > DISK_IMAGE_MMAP, > }; > > -#define MAX_DISK_IMAGES 4 > - > struct disk_image; > > struct disk_image_operations { > @@ -37,6 +37,7 @@ struct disk_image_operations { > int iovcount, void *param); > int (*flush)(struct disk_image *disk); > int (*close)(struct disk_image *disk); > + int (*submit)(struct disk_image *disk); > }; > > struct disk_image { > @@ -50,6 +51,9 @@ struct disk_image { > int evt; > #ifdef CONFIG_HAS_AIO > io_context_t ctx; > + struct iocb iocb[AIO_MAX]; > + struct iocb *iocb_ptrs[AIO_MAX]; > + u32 count; > #endif > }; > > diff --git a/tools/kvm/util/read-write.c b/tools/kvm/util/read-write.c > index 55473ba..4ccd554 100644 > --- a/tools/kvm/util/read-write.c > +++ b/tools/kvm/util/read-write.c > @@ -321,24 +321,20 @@ ssize_t pwritev_in_full(int fd, const struct iovec > *iov, int iovcnt, off_t offse > int aio_pwritev(io_context_t ctx, struct iocb *iocb, int fd, const struct > iovec *iov, int iovcnt, > off_t offset, int ev, void *param) > { > - struct iocb *ios[1] = { iocb }; > - > io_prep_pwritev(iocb, fd, iov, iovcnt, offset); > io_set_eventfd(iocb, ev); > iocb->data = param; > > - return io_submit(ctx, 1, ios); > + return 0; > } > > int aio_preadv(io_context_t ctx, struct iocb *iocb, int fd, const struct > iovec *iov, int iovcnt, > off_t offset, int ev, void *param) > { > - struct iocb *ios[1] = { iocb }; > - > io_prep_preadv(iocb, fd, iov, iovcnt, offset); > io_set_eventfd(iocb, ev); > iocb->data = param; > > - return io_submit(ctx, 1, ios); > + return 0; > } > #endif > \ No newline at end of file > diff --git a/tools/kvm/virtio/blk.c b/tools/kvm/virtio/blk.c > index d1a0197..153b11b 100644 > --- a/tools/kvm/virtio/blk.c > +++ b/tools/kvm/virtio/blk.c > @@ -128,6 +128,9 @@ static void virtio_blk_do_io(struct kvm *kvm, struct > virt_queue *vq, struct blk_ > > virtio_blk_do_io_request(kvm, req); > } > + > + if (bdev->disk->ops->submit) > + bdev->disk->ops->submit(bdev->disk); > } > > static void set_config(struct kvm *kvm, void *dev, u8 data, u32 offset) -- Asias He -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
