Re: [Qemu-devel] [PATCH 2/5] qemu-img bench: Sequential writes

["Denis V. Lunev" <den@openvz.org>]

On 06/03/2016 03:30 PM, Kevin Wolf wrote:
> This extends qemu-img bench with an option that makes it use sequential
> writes instead of reads for the test run.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   qemu-img-cmds.hx |  4 ++--
>   qemu-img.c       | 24 +++++++++++++++++++-----
>   qemu-img.texi    | 10 ++++++----
>   3 files changed, 27 insertions(+), 11 deletions(-)
>
> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
> index f3bd546..d651674 100644
> --- a/qemu-img-cmds.hx
> +++ b/qemu-img-cmds.hx
> @@ -10,9 +10,9 @@ STEXI
>   ETEXI
>   
>   DEF("bench", img_bench,
> -    "bench [-c count] [-d depth] [-f fmt] [-n] [-q] [-s buffer_size] [-t cache] filename")
> +    "bench [-c count] [-d depth] [-f fmt] [-n] [-q] [-s buffer_size] [-t cache] [-w] filename")
>   STEXI
> -@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [-n] [-q] [-s @var{buffer_size}] [-t @var{cache}] @var{filename}
> +@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [-n] [-q] [-s @var{buffer_size}] [-t @var{cache}] [-w] @var{filename}
>   ETEXI
>   
>   DEF("check", img_check,
> diff --git a/qemu-img.c b/qemu-img.c
> index d471d10..142efb1 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -3462,6 +3462,7 @@ out_no_progress:
>   typedef struct BenchData {
>       BlockBackend *blk;
>       uint64_t image_size;
> +    bool write;
>       int bufsize;
>       int nrreq;
>       int n;
> @@ -3487,8 +3488,13 @@ static void bench_cb(void *opaque, int ret)
>       }
>   
>       while (b->n > b->in_flight && b->in_flight < b->nrreq) {
> -        acb = blk_aio_preadv(b->blk, b->offset, b->qiov, 0,
> -                             bench_cb, b);
> +        if (b->write) {
> +            acb = blk_aio_pwritev(b->blk, b->offset, b->qiov, 0,
> +                                  bench_cb, b);
> +        } else {
> +            acb = blk_aio_preadv(b->blk, b->offset, b->qiov, 0,
> +                                 bench_cb, b);
> +        }
>           if (!acb) {
>               error_report("Failed to issue request");
>               exit(EXIT_FAILURE);
> @@ -3505,6 +3511,7 @@ static int img_bench(int argc, char **argv)
>       const char *fmt = NULL, *filename;
>       bool quiet = false;
>       bool image_opts = false;
> +    bool is_write = false;
>       int count = 75000;
>       int depth = 64;
>       size_t bufsize = 4096;
> @@ -3522,7 +3529,7 @@ static int img_bench(int argc, char **argv)
>               {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
>               {0, 0, 0, 0}
>           };
> -        c = getopt_long(argc, argv, "hc:d:f:nqs:t:", long_options, NULL);
> +        c = getopt_long(argc, argv, "hc:d:f:nqs:t:w", long_options, NULL);
>           if (c == -1) {
>               break;
>           }
> @@ -3585,6 +3592,10 @@ static int img_bench(int argc, char **argv)
>                   goto out;
>               }
>               break;
> +        case 'w':
> +            flags |= BDRV_O_RDWR;
> +            is_write = true;
> +            break;
>           case OPTION_IMAGE_OPTS:
>               image_opts = true;
>               break;
> @@ -3614,11 +3625,14 @@ static int img_bench(int argc, char **argv)
>           .bufsize    = bufsize,
>           .nrreq      = depth,
>           .n          = count,
> +        .write      = is_write,
>       };
> -    printf("Sending %d requests, %d bytes each, %d in parallel\n",
> -        data.n, data.bufsize, data.nrreq);
> +    printf("Sending %d %s requests, %d bytes each, %d in parallel\n",
> +           data.n, data.write ? "write" : "read", data.bufsize, data.nrreq);
>   
>       data.buf = blk_blockalign(blk, data.nrreq * data.bufsize);
> +    memset(data.buf, 0, data.nrreq * data.bufsize);
> +
using 0 could be controversal. Can you add -P option like one
in qemu-io to fill the pattern?