Commit ddd2ef2c authored by Denis V. Lunev's avatar Denis V. Lunev Committed by Stefan Hajnoczi
Browse files

block/parallels: improve image writing performance further 



Try to perform IO for the biggest continuous block possible.
All blocks abscent in the image are accounted in the same type
and preallocation is made for all of them at once.

The performance for sequential write is increased from 200 Mb/sec to
235 Mb/sec on my SSD HDD.

Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
Reviewed-by: default avatarRoman Kagan <rkagan@parallels.com>
Signed-off-by: default avatarRoman Kagan <rkagan@parallels.com>
Message-id: 1430207220-24458-28-git-send-email-den@openvz.org
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 19f5dc15

block/parallels.c

+23 −20
Original line number Diff line number Diff line
@@ -183,43 +183,47 @@ static int64_t block_status(BDRVParallelsState *s, int64_t sector_num, 
    return start_off;

}



static int64_t allocate_cluster(BlockDriverState *bs, int64_t sector_num)

static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num,

                                 int nb_sectors, int *pnum)

{

    BDRVParallelsState *s = bs->opaque;

    uint32_t idx, offset;

    int64_t pos;

    uint32_t idx, to_allocate, i;

    int64_t pos, space;



    idx = sector_num / s->tracks;

    offset = sector_num % s->tracks;

    pos = block_status(s, sector_num, nb_sectors, pnum);

    if (pos > 0) {

        return pos;

    }



    idx = sector_num / s->tracks;

    if (idx >= s->bat_size) {

        return -EINVAL;

    }

    if (s->bat_bitmap[idx] != 0) {

        return bat2sect(s, idx) + offset;

    }



    pos = bdrv_getlength(bs->file) >> BDRV_SECTOR_BITS;

    if (s->data_end + s->tracks > pos) {

    to_allocate = (sector_num + *pnum + s->tracks - 1) / s->tracks - idx;

    space = to_allocate * s->tracks;

    if (s->data_end + space > bdrv_getlength(bs->file) >> BDRV_SECTOR_BITS) {

        int ret;

        space += s->prealloc_size;

        if (s->prealloc_mode == PRL_PREALLOC_MODE_FALLOCATE) {

            ret = bdrv_write_zeroes(bs->file, s->data_end,

                                    s->prealloc_size, 0);

            ret = bdrv_write_zeroes(bs->file, s->data_end, space, 0);

        } else {

            ret = bdrv_truncate(bs->file,

                    (s->data_end + s->prealloc_size) << BDRV_SECTOR_BITS);

                                (s->data_end + space) << BDRV_SECTOR_BITS);

        }

        if (ret < 0) {

            return ret;

        }

    }

    pos = s->data_end;

    s->data_end += s->tracks;



    s->bat_bitmap[idx] = cpu_to_le32(pos / s->off_multiplier);

    for (i = 0; i < to_allocate; i++) {

        s->bat_bitmap[idx + i] = cpu_to_le32(s->data_end / s->off_multiplier);

        s->data_end += s->tracks;

        bitmap_set(s->bat_dirty_bmap,

                   bat_entry_off(idx) / s->bat_dirty_block, 1);

    }



    bitmap_set(s->bat_dirty_bmap, bat_entry_off(idx) / s->bat_dirty_block, 1);

    return bat2sect(s, idx) + offset;

    return bat2sect(s, idx) + sector_num % s->tracks;

}
@@ -287,14 +291,13 @@ static coroutine_fn int parallels_co_writev(BlockDriverState *bs, 
        int n, nbytes;



        qemu_co_mutex_lock(&s->lock);

        position = allocate_cluster(bs, sector_num);

        position = allocate_clusters(bs, sector_num, nb_sectors, &n);

        qemu_co_mutex_unlock(&s->lock);

        if (position < 0) {

            ret = (int)position;

            break;

        }



        n = cluster_remainder(s, sector_num, nb_sectors);

        nbytes = n << BDRV_SECTOR_BITS;



        qemu_iovec_reset(&hd_qiov);