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[src/trunk]: src Enhance disk metrics by calculating a weighted sum that is i...
details: https://anonhg.NetBSD.org/src/rev/4800e3841085
branches: trunk
changeset: 822170:4800e3841085
user: mlelstv <mlelstv%NetBSD.org@localhost>
date: Sun Mar 05 23:07:12 2017 +0000
description:
Enhance disk metrics by calculating a weighted sum that is incremented
by the number of concurrent I/O requests. Also introduce a new disk_wait()
function to measure requests waiting in a bufq.
iostat -y now reports data about waiting and active requests.
So far only drivers using dksubr and dk, ccd, wd and xbd collect data about
waiting requests.
diffstat:
share/man/man9/disk.9 | 76 ++++++++++++++---------
sys/arch/xen/xen/xbd_xenbus.c | 10 +-
sys/dev/ata/wd.c | 5 +-
sys/dev/ccd.c | 7 +-
sys/dev/dksubr.c | 10 ++-
sys/dev/dkwedge/dk.c | 5 +-
sys/kern/subr_disk.c | 14 +++-
sys/kern/subr_iostat.c | 135 ++++++++++++++++++++++++++++++++++-------
sys/sys/disk.h | 3 +-
sys/sys/iostat.h | 23 ++++++-
usr.bin/vmstat/drvstats.c | 72 +++++++++++++++------
usr.bin/vmstat/drvstats.h | 7 +-
usr.sbin/iostat/iostat.8 | 28 ++++++++-
usr.sbin/iostat/iostat.c | 112 ++++++++++++++++++++++++++++++++--
14 files changed, 400 insertions(+), 107 deletions(-)
diffs (truncated from 1050 to 300 lines):
diff -r f96f9b08d6f2 -r 4800e3841085 share/man/man9/disk.9
--- a/share/man/man9/disk.9 Sun Mar 05 22:24:29 2017 +0000
+++ b/share/man/man9/disk.9 Sun Mar 05 23:07:12 2017 +0000
@@ -1,4 +1,4 @@
-.\" $NetBSD: disk.9,v 1.43 2017/01/23 11:42:03 abhinav Exp $
+.\" $NetBSD: disk.9,v 1.44 2017/03/05 23:07:12 mlelstv Exp $
.\"
.\" Copyright (c) 1995, 1996 Jason R. Thorpe.
.\" All rights reserved.
@@ -40,6 +40,7 @@
.Nm disk_begindetach ,
.Nm disk_detach ,
.Nm disk_destroy ,
+.Nm disk_wait ,
.Nm disk_busy ,
.Nm disk_unbusy ,
.Nm disk_isbusy ,
@@ -61,6 +62,8 @@
.Ft void
.Fn disk_destroy "struct disk *"
.Ft void
+.Fn disk_wait "struct disk *"
+.Ft void
.Fn disk_busy "struct disk *"
.Ft void
.Fn disk_unbusy "struct disk *" "long bcount" "int read"
@@ -167,19 +170,25 @@
.It Fn disk_destroy
Release resources used by the disk structure when it is no longer
required.
+.It Fn disk_wait
+Disk timings are measured by counting the number of queued
+requests (wait counter) and requests issued to the hardware (busy counter)
+and keeping timestamp when the counters change. The time interval between
+two changes of a counter is accumulated into a total and also multiplied
+by the counter value and the accumulated into a sum. Both values can be
+used to determine how much time is spent in the driver queue or in-flight
+to the hardware as well as the average number of requests in either state.
+.Fn disk_wait
+increment the disk's wait counter and handles the accumulation.
.It Fn disk_busy
-Increment the disk's
-.Dq busy counter .
-If this counter goes from 0 to 1, set the timestamp corresponding to
-this transfer.
+Decrements the disk's wait counter and increments the disk's
+.Dq busy counter ,
+and handles either accumulation. If the wait counter is still zero, it
+is assumed that the driver hasn't been updated to call
+.Fn disk_wait ,
+then only the values from the busy counter are available.
.It Fn disk_unbusy
-Decrement a disk's busy counter.
-If the count drops below zero, panic.
-Get the current time, subtract it from the disk's timestamp, and add
-the difference to the disk's running total.
-Set the disk's timestamp to the current time.
-If the provided byte count is greater than 0, add it to the disk's
-running total and increment the number of transfers performed by the disk.
+Decrement the disk's busy counter and handles the accumulation.
The third argument
.Ar read
specifies the direction of I/O;
@@ -212,6 +221,7 @@
.Fn disk_begindetach ,
.Fn disk_detach ,
.Fn disk_destroy ,
+.Fn disk_wait ,
.Fn disk_busy ,
.Fn disk_unbusy ,
and
@@ -403,8 +413,9 @@
.Pp
Once the disk is attached, metrics may be gathered on that disk.
In order to gather metrics data, the driver must tell the framework when
-the disk starts and stops operations.
+the disk queues, starts and stops operations.
This functionality is provided by the
+.Fn disk_wait ,
.Fn disk_busy
and
.Fn disk_unbusy
@@ -413,6 +424,7 @@
.Nm struct disk
is part of device driver private data it needs to be guarded.
Mutual exclusion must be done by driver
+.Fn disk_wait ,
.Fn disk_busy
and
.Fn disk_unbusy
@@ -423,8 +435,22 @@
sent, e.g.:
.Bd -literal
void
-foostart(sc)
- struct foo_softc *sc;
+foostrategy(struct buf *bp)
+{
+ [ . . . ]
+
+ mutex_enter(\*[Am]sc-\*[Gt]sc_dk_mtx);
+ disk_wait(\*[Am]sc-\*[Gt]sc_dk);
+
+ /* Put buffer onto drive's transfer queue */
+
+ mutex_exit(\*[Am]sc-\*[Gt]sc_dk_mtx);
+
+ foostart(sc);
+}
+
+void
+foostart(struct foo_softc *sc)
{
[ . . . ]
@@ -444,26 +470,15 @@
}
.Ed
.Pp
-When
-.Fn disk_busy
-is called, a timestamp is taken if the disk's busy counter moves from
-0 to 1, indicating the disk has gone from an idle to non-idle state.
-At the end of a transaction, the
+The routine
.Fn disk_unbusy
-routine should be called.
-This routine performs some consistency checks,
-such as ensuring that the calls to
+performs some consistency checks, such as ensuring that the calls to
.Fn disk_busy
and
.Fn disk_unbusy
are balanced.
-This routine also performs the actual metrics calculation.
-A timestamp is taken and the difference from the timestamp taken in
-.Fn disk_busy
-is added to the disk's total running time.
-The disk's timestamp is then updated in case there is more than one
-pending transfer on the disk.
-A byte count is also added to the disk's running total, and if greater than
+It also performs the final steps of the metrics calcuation.
+A byte count is added to the disk's running total, and if greater than
zero, the number of transfers the disk has performed is incremented.
The third argument
.Ar read
@@ -506,6 +521,7 @@
is used to get status of disk device it returns true if device is
currently busy and false if it is not.
Like
+.Fn disk_wait ,
.Fn disk_busy
and
.Fn disk_unbusy
diff -r f96f9b08d6f2 -r 4800e3841085 sys/arch/xen/xen/xbd_xenbus.c
--- a/sys/arch/xen/xen/xbd_xenbus.c Sun Mar 05 22:24:29 2017 +0000
+++ b/sys/arch/xen/xen/xbd_xenbus.c Sun Mar 05 23:07:12 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: xbd_xenbus.c,v 1.75 2015/10/25 07:51:16 maxv Exp $ */
+/* $NetBSD: xbd_xenbus.c,v 1.76 2017/03/05 23:07:12 mlelstv Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -50,7 +50,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.75 2015/10/25 07:51:16 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.76 2017/03/05 23:07:12 mlelstv Exp $");
#include "opt_xen.h"
@@ -327,7 +327,7 @@
sc->sc_shutdown = BLKIF_SHUTDOWN_LOCAL;
/* wait for requests to complete */
while (sc->sc_backend_status == BLKIF_STATE_CONNECTED &&
- sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0)
+ disk_isbusy(&sc->sc_dksc.sc_dkdev))
tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach", hz/2);
xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateClosing);
@@ -392,7 +392,7 @@
s = splbio();
/* wait for requests to complete, then suspend device */
while (sc->sc_backend_status == BLKIF_STATE_CONNECTED &&
- sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0)
+ disk_isbusy(&sc->sc_dksc.sc_dkdev))
tsleep(xbd_xenbus_suspend, PRIBIO, "xbdsuspend", hz/2);
hypervisor_mask_event(sc->sc_evtchn);
@@ -530,7 +530,7 @@
sc->sc_shutdown = BLKIF_SHUTDOWN_REMOTE;
/* wait for requests to complete */
while (sc->sc_backend_status == BLKIF_STATE_CONNECTED &&
- sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0)
+ disk_isbusy(&sc->sc_dksc.sc_dkdev))
tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach", hz/2);
splx(s);
xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateClosed);
diff -r f96f9b08d6f2 -r 4800e3841085 sys/dev/ata/wd.c
--- a/sys/dev/ata/wd.c Sun Mar 05 22:24:29 2017 +0000
+++ b/sys/dev/ata/wd.c Sun Mar 05 23:07:12 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: wd.c,v 1.427 2016/11/20 02:35:19 pgoyette Exp $ */
+/* $NetBSD: wd.c,v 1.428 2017/03/05 23:07:12 mlelstv Exp $ */
/*
* Copyright (c) 1998, 2001 Manuel Bouyer. All rights reserved.
@@ -54,7 +54,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: wd.c,v 1.427 2016/11/20 02:35:19 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: wd.c,v 1.428 2017/03/05 23:07:12 mlelstv Exp $");
#include "opt_ata.h"
@@ -605,6 +605,7 @@
/* Queue transfer on drive, activate drive and controller if idle. */
s = splbio();
+ disk_wait(&wd->sc_dk);
bufq_put(wd->sc_q, bp);
wdstart(wd);
splx(s);
diff -r f96f9b08d6f2 -r 4800e3841085 sys/dev/ccd.c
--- a/sys/dev/ccd.c Sun Mar 05 22:24:29 2017 +0000
+++ b/sys/dev/ccd.c Sun Mar 05 23:07:12 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ccd.c,v 1.168 2016/11/20 02:35:19 pgoyette Exp $ */
+/* $NetBSD: ccd.c,v 1.169 2017/03/05 23:07:12 mlelstv Exp $ */
/*-
* Copyright (c) 1996, 1997, 1998, 1999, 2007, 2009 The NetBSD Foundation, Inc.
@@ -88,7 +88,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ccd.c,v 1.168 2016/11/20 02:35:19 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ccd.c,v 1.169 2017/03/05 23:07:12 mlelstv Exp $");
#if defined(_KERNEL_OPT)
#include "opt_compat_netbsd.h"
@@ -815,10 +815,11 @@
KASSERT(mutex_owned(cs->sc_iolock));
- disk_busy(&cs->sc_dkdev);
bp = bufq_get(cs->sc_bufq);
KASSERT(bp != NULL);
+ disk_busy(&cs->sc_dkdev);
+
#ifdef DEBUG
if (ccddebug & CCDB_FOLLOW)
printf("ccdstart(%s, %p)\n", cs->sc_xname, bp);
diff -r f96f9b08d6f2 -r 4800e3841085 sys/dev/dksubr.c
--- a/sys/dev/dksubr.c Sun Mar 05 22:24:29 2017 +0000
+++ b/sys/dev/dksubr.c Sun Mar 05 23:07:12 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: dksubr.c,v 1.95 2017/02/25 15:19:00 mlelstv Exp $ */
+/* $NetBSD: dksubr.c,v 1.96 2017/03/05 23:07:12 mlelstv Exp $ */
/*-
* Copyright (c) 1996, 1997, 1998, 1999, 2002, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.95 2017/02/25 15:19:00 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.96 2017/03/05 23:07:12 mlelstv Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -339,6 +339,7 @@
* Queue buffer only
*/
mutex_enter(&dksc->sc_iolock);
+ disk_wait(&dksc->sc_dkdev);
bufq_put(dksc->sc_bufq, bp);
mutex_exit(&dksc->sc_iolock);
@@ -375,8 +376,10 @@
mutex_enter(&dksc->sc_iolock);
- if (bp != NULL)
+ if (bp != NULL) {
+ disk_wait(&dksc->sc_dkdev);
bufq_put(dksc->sc_bufq, bp);
+ }
/*
* If another thread is running the queue, increment
@@ -417,6 +420,7 @@
if (error == EAGAIN) {
dksc->sc_deferred = bp;
disk_unbusy(&dksc->sc_dkdev, 0, (bp->b_flags & B_READ));
+ disk_wait(&dksc->sc_dkdev);
break;
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