[3/5] qemu-img bench: Make start offset configurable

This patch adds an option the specify the offset of the first request
made by qemu-img bench. This allows to benchmark misaligned requests.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-img-cmds.hx |  4 ++--
 qemu-img.c       | 23 ++++++++++++++++++++---
 qemu-img.texi    |  5 +++--
 3 files changed, 25 insertions(+), 7 deletions(-)

On 06/03/2016 03:30 PM, Kevin Wolf wrote:
> This patch adds an option the specify the offset of the first request
> made by qemu-img bench. This allows to benchmark misaligned requests.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   qemu-img-cmds.hx |  4 ++--
>   qemu-img.c       | 23 ++++++++++++++++++++---
>   qemu-img.texi    |  5 +++--
>   3 files changed, 25 insertions(+), 7 deletions(-)
>
> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
> index d651674..b9b521e 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] [-w] filename")
> +    "bench [-c count] [-d depth] [-f fmt] [-n] [-o offset] [-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}] [-w] @var{filename}
> +@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [-n] [-o @var{offset}] [-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 142efb1..fcac8b8 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -3514,6 +3514,7 @@ static int img_bench(int argc, char **argv)
>       bool is_write = false;
>       int count = 75000;
>       int depth = 64;
> +    int64_t offset = 0;
>       size_t bufsize = 4096;
>       int64_t image_size;
>       BlockBackend *blk = NULL;
> @@ -3529,7 +3530,7 @@ 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:w", long_options, NULL);
> +        c = getopt_long(argc, argv, "hc:d:f:no:qs:t:w", long_options, NULL);
>           if (c == -1) {
>               break;
>           }
> @@ -3567,6 +3568,19 @@ static int img_bench(int argc, char **argv)
>           case 'n':
>               flags |= BDRV_O_NATIVE_AIO;
>               break;
> +        case 'o':
> +        {
> +            char *end;
> +            errno = 0;
> +            offset = qemu_strtosz_suffix(optarg, &end,
> +                                         QEMU_STRTOSZ_DEFSUFFIX_B);
> +            if (offset < 0|| *end) {
> +                error_report("Invalid offset specified");
> +                return 1;
> +            }
> +            break;
> +        }
> +            break;
>           case 'q':
>               quiet = true;
>               break;
> @@ -3625,10 +3639,13 @@ static int img_bench(int argc, char **argv)
>           .bufsize    = bufsize,
>           .nrreq      = depth,
>           .n          = count,
> +        .offset     = offset,
>           .write      = is_write,
>       };
> -    printf("Sending %d %s requests, %d bytes each, %d in parallel\n",
> -           data.n, data.write ? "write" : "read", data.bufsize, data.nrreq);
> +    printf("Sending %d %s requests, %d bytes each, %d in parallel "
> +           "(starting at offset %" PRId64 ")\n",
> +           data.n, data.write ? "write" : "read", data.bufsize, data.nrreq,
> +           data.offset);
>   
>       data.buf = blk_blockalign(blk, data.nrreq * data.bufsize);
>       memset(data.buf, 0, data.nrreq * data.bufsize);
> diff --git a/qemu-img.texi b/qemu-img.texi
> index 34e94db..c37380e 100644
> --- a/qemu-img.texi
> +++ b/qemu-img.texi
> @@ -131,13 +131,14 @@ 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}] [-w] @var{filename}
> +@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [-n] [-o @var{offset}] [-q] [-s @var{buffer_size}] [-t @var{cache}] [-w] @var{filename}
>   
>   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.
> +bytes in size, and with @var{depth} requests in parallel. The first request
> +starts at the position given by @var{offset}.
>   
>   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
Reviewed-by: Denis V. Lunev <den@openvz.org>