Author: mm
Date: Sun May 16 07:16:28 2010
New Revision: 208130
URL: http://svn.freebsd.org/changeset/base/208130
Log:
Fix perfomance problem with ZFS prefetch caching [1]
Add statistics for ZFS prefetch (sysctl kstat.zfs.misc.zfetchstats)
Partial import of OpenSolaris onnv revision 10474:0e96dd3b905a
Reported by: jh...@dataix.net (private e-mail) [1]
Approved by: pjd, delphij (mentor)
Obtained from: OpenSolaris (Bug ID 6859997, 6868951)
MFC after: 3 days
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_zfetch.h
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c Sun May 16
06:40:05 2010 (r208129)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c Sun May 16
07:16:28 2010 (r208130)
@@ -1192,6 +1192,7 @@ dmu_init(void)
{
dbuf_init();
dnode_init();
+ zfetch_init();
arc_init();
l2arc_init();
}
@@ -1200,6 +1201,7 @@ void
dmu_fini(void)
{
arc_fini();
+ zfetch_fini();
dnode_fini();
dbuf_fini();
l2arc_fini();
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c Sun May
16 06:40:05 2010 (r208129)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_zfetch.c Sun May
16 07:16:28 2010 (r208130)
@@ -19,18 +19,17 @@
* CDDL HEADER END
*/
/*
- * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
-#pragma ident "%Z%%M% %I% %E% SMI"
-
#include <sys/zfs_context.h>
#include <sys/dnode.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_zfetch.h>
#include <sys/dmu.h>
#include <sys/dbuf.h>
+#include <sys/kstat.h>
/*
* I'm against tune-ables, but these should probably exist as tweakable globals
@@ -77,6 +76,41 @@ static zstream_t *dmu_zfetch_stream_recl
static void dmu_zfetch_stream_remove(zfetch_t *, zstream_t *);
static int dmu_zfetch_streams_equal(zstream_t *, zstream_t *);
+typedef struct zfetch_stats {
+ kstat_named_t zfetchstat_hits;
+ kstat_named_t zfetchstat_misses;
+ kstat_named_t zfetchstat_colinear_hits;
+ kstat_named_t zfetchstat_colinear_misses;
+ kstat_named_t zfetchstat_stride_hits;
+ kstat_named_t zfetchstat_stride_misses;
+ kstat_named_t zfetchstat_reclaim_successes;
+ kstat_named_t zfetchstat_reclaim_failures;
+ kstat_named_t zfetchstat_stream_resets;
+ kstat_named_t zfetchstat_stream_noresets;
+ kstat_named_t zfetchstat_bogus_streams;
+} zfetch_stats_t;
+
+static zfetch_stats_t zfetch_stats = {
+ { "hits", KSTAT_DATA_UINT64 },
+ { "misses", KSTAT_DATA_UINT64 },
+ { "colinear_hits", KSTAT_DATA_UINT64 },
+ { "colinear_misses", KSTAT_DATA_UINT64 },
+ { "stride_hits", KSTAT_DATA_UINT64 },
+ { "stride_misses", KSTAT_DATA_UINT64 },
+ { "reclaim_successes", KSTAT_DATA_UINT64 },
+ { "reclaim_failures", KSTAT_DATA_UINT64 },
+ { "streams_resets", KSTAT_DATA_UINT64 },
+ { "streams_noresets", KSTAT_DATA_UINT64 },
+ { "bogus_streams", KSTAT_DATA_UINT64 },
+};
+
+#define ZFETCHSTAT_INCR(stat, val) \
+ atomic_add_64(&zfetch_stats.stat.value.ui64, (val));
+
+#define ZFETCHSTAT_BUMP(stat) ZFETCHSTAT_INCR(stat, 1);
+
+kstat_t *zfetch_ksp;
+
/*
* Given a zfetch structure and a zstream structure, determine whether the
* blocks to be read are part of a co-linear pair of existing prefetch
@@ -213,6 +247,29 @@ dmu_zfetch_dofetch(zfetch_t *zf, zstream
zs->zst_last = LBOLT;
}
+void
+zfetch_init(void)
+{
+
+ zfetch_ksp = kstat_create("zfs", 0, "zfetchstats", "misc",
+ KSTAT_TYPE_NAMED, sizeof (zfetch_stats) / sizeof (kstat_named_t),
+ KSTAT_FLAG_VIRTUAL);
+
+ if (zfetch_ksp != NULL) {
+ zfetch_ksp->ks_data = &zfetch_stats;
+ kstat_install(zfetch_ksp);
+ }
+}
+
+void
+zfetch_fini(void)
+{
+ if (zfetch_ksp != NULL) {
+ kstat_delete(zfetch_ksp);
+ zfetch_ksp = NULL;
+ }
+}
+
/*
* This takes a pointer to a zfetch structure and a dnode. It performs the
* necessary setup for the zfetch structure, grokking data from the
@@ -283,7 +340,7 @@ dmu_zfetch_fetchsz(dnode_t *dn, uint64_t
}
/*
- * given a zfetch and a zsearch structure, see if there is an associated
zstream
+ * given a zfetch and a zstream structure, see if there is an associated
zstream
* for this block read. If so, it starts a prefetch for the stream it
* located and returns true, otherwise it returns false
*/
@@ -315,6 +372,7 @@ top:
*/
if (zs->zst_len == 0) {
/* bogus stream */
+ ZFETCHSTAT_BUMP(zfetchstat_bogus_streams);
continue;
}
@@ -324,9 +382,14 @@ top:
*/
if (zh->zst_offset >= zs->zst_offset &&
zh->zst_offset < zs->zst_offset + zs->zst_len) {
- /* already fetched */
- rc = 1;
- goto out;
+ if (prefetched) {
+ /* already fetched */
+ ZFETCHSTAT_BUMP(zfetchstat_stride_hits);
+ rc = 1;
+ goto out;
+ } else {
+ ZFETCHSTAT_BUMP(zfetchstat_stride_misses);
+ }
}
/*
@@ -439,6 +502,7 @@ top:
if (reset) {
zstream_t *remove = zs;
+ ZFETCHSTAT_BUMP(zfetchstat_stream_resets);
rc = 0;
mutex_exit(&zs->zst_lock);
rw_exit(&zf->zf_rwlock);
@@ -457,6 +521,7 @@ top:
}
}
} else {
+ ZFETCHSTAT_BUMP(zfetchstat_stream_noresets);
rc = 1;
dmu_zfetch_dofetch(zf, zs);
mutex_exit(&zs->zst_lock);
@@ -513,13 +578,12 @@ dmu_zfetch_stream_insert(zfetch_t *zf, z
zs_next = list_next(&zf->zf_stream, zs_walk);
if (dmu_zfetch_streams_equal(zs_walk, zs)) {
- return (0);
+ return (0);
}
}
list_insert_head(&zf->zf_stream, zs);
zf->zf_stream_cnt++;
-
return (1);
}
@@ -623,8 +687,15 @@ dmu_zfetch(zfetch_t *zf, uint64_t offset
P2ALIGN(offset, blksz)) >> blkshft;
fetched = dmu_zfetch_find(zf, &zst, prefetched);
- if (!fetched) {
- fetched = dmu_zfetch_colinear(zf, &zst);
+ if (fetched) {
+ ZFETCHSTAT_BUMP(zfetchstat_hits);
+ } else {
+ ZFETCHSTAT_BUMP(zfetchstat_misses);
+ if (fetched = dmu_zfetch_colinear(zf, &zst)) {
+ ZFETCHSTAT_BUMP(zfetchstat_colinear_hits);
+ } else {
+ ZFETCHSTAT_BUMP(zfetchstat_colinear_misses);
+ }
}
if (!fetched) {
@@ -634,11 +705,14 @@ dmu_zfetch(zfetch_t *zf, uint64_t offset
* we still couldn't find a stream, drop the lock, and allocate
* one if possible. Otherwise, give up and go home.
*/
- if (newstream == NULL) {
+ if (newstream) {
+ ZFETCHSTAT_BUMP(zfetchstat_reclaim_successes);
+ } else {
uint64_t maxblocks;
uint32_t max_streams;
uint32_t cur_streams;
+ ZFETCHSTAT_BUMP(zfetchstat_reclaim_failures);
cur_streams = zf->zf_stream_cnt;
maxblocks = zf->zf_dnode->dn_maxblkid;
@@ -651,7 +725,6 @@ dmu_zfetch(zfetch_t *zf, uint64_t offset
if (cur_streams >= max_streams) {
return;
}
-
newstream = kmem_zalloc(sizeof (zstream_t), KM_SLEEP);
}
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_zfetch.h
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_zfetch.h
Sun May 16 06:40:05 2010 (r208129)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_zfetch.h
Sun May 16 07:16:28 2010 (r208130)
@@ -19,15 +19,13 @@
* CDDL HEADER END
*/
/*
- * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#ifndef _DFETCH_H
#define _DFETCH_H
-#pragma ident "%Z%%M% %I% %E% SMI"
-
#include <sys/zfs_context.h>
#ifdef __cplusplus
@@ -63,6 +61,9 @@ typedef struct zfetch {
uint64_t zf_alloc_fail; /* # of failed attempts to alloc strm */
} zfetch_t;
+void zfetch_init(void);
+void zfetch_fini(void);
+
void dmu_zfetch_init(zfetch_t *, struct dnode *);
void dmu_zfetch_rele(zfetch_t *);
void dmu_zfetch(zfetch_t *, uint64_t, uint64_t, int);
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