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

[Kevin Wolf <kwolf@redhat.com>]

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);
+
     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..34e94db 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -131,11 +131,13 @@ 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] [-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
-- 
1.8.3.1