Re: [Qemu-devel] [PATCH v2 2/5] qemu-img bench: Sequential writes

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

On 06/06/2016 03:45 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       | 38 +++++++++++++++++++++++++++++++++-----
>   qemu-img.texi    | 13 +++++++++----
>   3 files changed, 44 insertions(+), 11 deletions(-)
>
> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
> index f3bd546..baca85e 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] [--pattern=pattern] [-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] [--pattern=@var{pattern}] [-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..85d1353 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -53,6 +53,7 @@ enum {
>       OPTION_BACKING_CHAIN = 257,
>       OPTION_OBJECT = 258,
>       OPTION_IMAGE_OPTS = 259,
> +    OPTION_PATTERN = 260,
>   };
>   
>   typedef enum OutputFormat {
> @@ -3462,6 +3463,7 @@ out_no_progress:
>   typedef struct BenchData {
>       BlockBackend *blk;
>       uint64_t image_size;
> +    bool write;
>       int bufsize;
>       int nrreq;
>       int n;
> @@ -3487,8 +3489,13 @@ 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);
> @@ -3505,9 +3512,11 @@ 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;
> +    int pattern = 0;
>       int64_t image_size;
>       BlockBackend *blk = NULL;
>       BenchData data = {};
> @@ -3520,9 +3529,10 @@ static int img_bench(int argc, char **argv)
>           static const struct option long_options[] = {
>               {"help", no_argument, 0, 'h'},
>               {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
> +            {"pattern", required_argument, 0, OPTION_PATTERN},
>               {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 +3595,21 @@ static int img_bench(int argc, char **argv)
>                   goto out;
>               }
>               break;
> +        case 'w':
> +            flags |= BDRV_O_RDWR;
> +            is_write = true;
> +            break;
> +        case OPTION_PATTERN:
> +        {
> +            char *end;
> +            errno = 0;
> +            pattern = strtoul(optarg, &end, 0);
> +            if (errno || *end || pattern > 0xff) {
> +                error_report("Invalid pattern byte specified");
> +                return 1;
> +            }
> +            break;
> +        }
>           case OPTION_IMAGE_OPTS:
>               image_opts = true;
>               break;
> @@ -3614,11 +3639,14 @@ 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, pattern, data.nrreq * data.bufsize);
> +
>       data.qiov = g_new(QEMUIOVector, data.nrreq);
>       for (i = 0; i < data.nrreq; i++) {
>           qemu_iovec_init(&data.qiov[i], 1);
> diff --git a/qemu-img.texi b/qemu-img.texi
> index b6b28e3..c477fbf 100644
> --- a/qemu-img.texi
> +++ b/qemu-img.texi
> @@ -131,16 +131,21 @@ Skip the creation of the target volume
>   Command description:
>   
>   @table @option
> -@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] [--pattern=@var{pattern}] [-q] [-s @var{buffer_size}] [-t @var{cache}] [-w] @var{filename}
>   
> -Run a simple sequential read benchmark on the specified image. A total number
> -of @var{count} I/O requests is performed, each @var{buffer_size} bytes in size,
> -and with @var{depth} requests in parallel.
> +Run a simple sequential I/O benchmark on the specified image. If @code{-w} is
> +specified, a write test is performed, otherwise a read test is performed.
> +
> +A total number of @var{count} I/O requests is performed, each @var{buffer_size}
> +bytes in size, and with @var{depth} requests in parallel.
>   
>   If @code{-n} is specified, the native AIO backend is used if possible. On
>   Linux, this option only works if @code{-t none} or @code{-t directsync} is
>   specified as well.
>   
> +For write tests, by default a buffer filled with zeros is written. This can be
> +overridden with a pattern byte specified by @var{pattern}.
> +
>   @item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] [-T @var{src_cache}] @var{filename}
>   
>   Perform a consistency check on the disk image @var{filename}. The command can
Reviewed-by: Denis V. Lunev <den@openvz.org>