This patch collects per-block-device statistics and allows them to be displayed in the monitor through a 'info blockstats' command. It generalises the VMDK-only support for this which was added to KVM's version of QEMU.
Screenshot showing 'info blockstats' command being run for a Solaris guest which is doing some moderate disk activity:
http://www.annexia.org/tmp/Screenshot-QEMU-2.png Rich.[1] Previous patch was: http://lists.gnu.org/archive/html/qemu-devel/2007-11/msg00489.html
-- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903
Index: block.c
===================================================================
RCS file: /sources/qemu/qemu/block.c,v
retrieving revision 1.49
diff -u -r1.49 block.c
--- block.c 18 Nov 2007 01:44:35 -0000 1.49
+++ block.c 27 Nov 2007 11:33:04 -0000
@@ -521,8 +521,11 @@
return ret;
else if (ret != len)
return -EINVAL;
- else
+ else {
+ bs->rd_bytes += (unsigned) len;
+ bs->rd_ops ++;
return 0;
+ }
} else {
return drv->bdrv_read(bs, sector_num, buf, nb_sectors);
}
@@ -553,8 +556,11 @@
return ret;
else if (ret != len)
return -EIO;
- else
+ else {
+ bs->wr_bytes += (unsigned) len;
+ bs->wr_ops ++;
return 0;
+ }
} else {
return drv->bdrv_write(bs, sector_num, buf, nb_sectors);
}
@@ -902,6 +908,24 @@
term_printf("\n");
}
}
+
+/* The "info blockstats" command. */
+void bdrv_info_stats (void)
+{
+ BlockDriverState *bs;
+
+ for (bs = bdrv_first; bs != NULL; bs = bs->next) {
+ term_printf ("%s:"
+ " rd_bytes=%" PRIu64
+ " wr_bytes=%" PRIu64
+ " rd_operations=%" PRIu64
+ " wr_operations=%" PRIu64
+ "\n",
+ bs->device_name,
+ bs->rd_bytes, bs->wr_bytes,
+ bs->rd_ops, bs->wr_ops);
+ }
+}
#endif
void bdrv_get_backing_filename(BlockDriverState *bs,
@@ -1064,6 +1088,7 @@
BlockDriverCompletionFunc *cb, void *opaque)
{
BlockDriver *drv = bs->drv;
+ BlockDriverAIOCB *ret;
if (!drv)
return NULL;
@@ -1076,7 +1101,15 @@
buf += 512;
}
- return drv->bdrv_aio_read(bs, sector_num, buf, nb_sectors, cb, opaque);
+ ret = drv->bdrv_aio_read(bs, sector_num, buf, nb_sectors, cb, opaque);
+
+ if (ret) {
+ /* Update stats even though technically transfer has not happened. */
+ bs->rd_bytes += (unsigned) nb_sectors * SECTOR_SIZE;
+ bs->rd_ops ++;
+ }
+
+ return ret;
}
BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
@@ -1084,6 +1117,7 @@
BlockDriverCompletionFunc *cb, void *opaque)
{
BlockDriver *drv = bs->drv;
+ BlockDriverAIOCB *ret;
if (!drv)
return NULL;
@@ -1093,7 +1127,15 @@
memcpy(bs->boot_sector_data, buf, 512);
}
- return drv->bdrv_aio_write(bs, sector_num, buf, nb_sectors, cb, opaque);
+ ret = drv->bdrv_aio_write(bs, sector_num, buf, nb_sectors, cb, opaque);
+
+ if (ret) {
+ /* Update stats even though technically transfer has not happened. */
+ bs->wr_bytes += (unsigned) nb_sectors * SECTOR_SIZE;
+ bs->wr_ops ++;
+ }
+
+ return ret;
}
void bdrv_aio_cancel(BlockDriverAIOCB *acb)
Index: block.h
===================================================================
RCS file: /sources/qemu/qemu/block.h,v
retrieving revision 1.2
diff -u -r1.2 block.h
--- block.h 17 Nov 2007 17:14:37 -0000 1.2
+++ block.h 27 Nov 2007 11:33:04 -0000
@@ -47,6 +47,7 @@
#ifndef QEMU_IMG
void bdrv_info(void);
+void bdrv_info_stats(void);
#endif
void bdrv_init(void);
Index: block_int.h
===================================================================
RCS file: /sources/qemu/qemu/block_int.h,v
retrieving revision 1.14
diff -u -r1.14 block_int.h
--- block_int.h 11 Nov 2007 02:51:16 -0000 1.14
+++ block_int.h 27 Nov 2007 11:33:04 -0000
@@ -114,6 +114,12 @@
void *sync_aiocb;
+ /* I/O stats (display with "info blockstats"). */
+ uint64_t rd_bytes;
+ uint64_t wr_bytes;
+ uint64_t rd_ops;
+ uint64_t wr_ops;
+
/* NOTE: the following infos are only hints for real hardware
drivers. They are not used by the block driver */
int cyls, heads, secs, translation;
Index: monitor.c
===================================================================
RCS file: /sources/qemu/qemu/monitor.c,v
retrieving revision 1.87
diff -u -r1.87 monitor.c
--- monitor.c 18 Nov 2007 01:44:35 -0000 1.87
+++ monitor.c 27 Nov 2007 11:33:05 -0000
@@ -260,6 +260,11 @@
bdrv_info();
}
+static void do_info_blockstats(void)
+{
+ bdrv_info_stats();
+}
+
/* get the current CPU defined by the user */
static int mon_set_cpu(int cpu_index)
{
@@ -1332,6 +1337,8 @@
"", "show the network state" },
{ "block", "", do_info_block,
"", "show the block devices" },
+ { "blockstats", "", do_info_blockstats,
+ "", "show block device statistics" },
{ "registers", "", do_info_registers,
"", "show the cpu registers" },
{ "cpus", "", do_info_cpus,
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