This is an updated patch for collecting block device statistics. Thanks
to several people on #qemu channel for giving me feedback about the
first version[1].
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 - 1.49
+++ block.c 27 Nov 2007 11:33:04 -
@@ -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 - 1.2
+++ block.h 27 Nov 2007 11:33:04 -
@@ -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 - 1.14
+++ block_int.h 27 Nov 2007 11:33:04 -
@@ -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 - 1.87
+++ monitor.c 27 Nov 2007 11:33:05 -
@@ -260,6 +260,11 @@
bdrv_info();
}
+static void
