diff options
Diffstat (limited to 'module/zfs/spa_stats.c')
| -rw-r--r-- | module/zfs/spa_stats.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/module/zfs/spa_stats.c b/module/zfs/spa_stats.c new file mode 100644 index 000000000..271a3c312 --- /dev/null +++ b/module/zfs/spa_stats.c @@ -0,0 +1,248 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ + +#include <sys/zfs_context.h> +#include <sys/spa_impl.h> + +/* + * Keeps stats on last N reads per spa_t, disabled by default. + */ +int zfs_read_history = 0; + +/* + * Include cache hits in history, disabled by default. + */ +int zfs_read_history_hits = 0; + +/* + * ========================================================================== + * SPA Read History Routines + * ========================================================================== + */ + +/* + * Read statistics - Information exported regarding each arc_read call + */ +typedef struct spa_read_history { + uint64_t uid; /* unique identifier */ + hrtime_t start; /* time read completed */ + uint64_t objset; /* read from this objset */ + uint64_t object; /* read of this object number */ + uint64_t level; /* block's indirection level */ + uint64_t blkid; /* read of this block id */ + char origin[24]; /* read originated from here */ + uint32_t aflags; /* ARC flags (cached, prefetch, etc.) */ + pid_t pid; /* PID of task doing read */ + char comm[16]; /* process name of task doing read */ + list_node_t srh_link; +} spa_read_history_t; + +static int +spa_read_history_headers(char *buf, size_t size) +{ + size = snprintf(buf, size - 1, "%-8s %-16s %-8s %-8s %-8s %-8s %-8s " + "%-24s %-8s %-16s\n", "UID", "start", "objset", "object", + "level", "blkid", "aflags", "origin", "pid", "process"); + buf[size] = '\0'; + + return (0); +} + +static int +spa_read_history_data(char *buf, size_t size, void *data) +{ + spa_read_history_t *srh = (spa_read_history_t *)data; + + size = snprintf(buf, size - 1, "%-8llu %-16llu 0x%-6llx " + "%-8lli %-8lli %-8lli 0x%-6x %-24s %-8i %-16s\n", + (u_longlong_t)srh->uid, srh->start, + (longlong_t)srh->objset, (longlong_t)srh->object, + (longlong_t)srh->level, (longlong_t)srh->blkid, + srh->aflags, srh->origin, srh->pid, srh->comm); + buf[size] = '\0'; + + return (0); +} + +/* + * Calculate the address for the next spa_stats_history_t entry. The + * ssh->lock will be held until ksp->ks_ndata entries are processed. + */ +static void * +spa_read_history_addr(kstat_t *ksp, loff_t n) +{ + spa_t *spa = ksp->ks_private; + spa_stats_history_t *ssh = &spa->spa_stats.read_history; + + ASSERT(MUTEX_HELD(&ssh->lock)); + + if (n == 0) + ssh->private = list_tail(&ssh->list); + else if (ssh->private) + ssh->private = list_prev(&ssh->list, ssh->private); + + return (ssh->private); +} + +/* + * When the kstat is written discard all spa_read_history_t entires. The + * ssh->lock will be held until ksp->ks_ndata entries are processed. + */ +static int +spa_read_history_update(kstat_t *ksp, int rw) +{ + spa_t *spa = ksp->ks_private; + spa_stats_history_t *ssh = &spa->spa_stats.read_history; + + if (rw == KSTAT_WRITE) { + spa_read_history_t *srh; + + while ((srh = list_remove_head(&ssh->list))) { + ssh->size--; + kmem_free(srh, sizeof(spa_read_history_t)); + } + + ASSERT3U(ssh->size, ==, 0); + } + + ksp->ks_ndata = ssh->size; + ksp->ks_data_size = ssh->size * sizeof(spa_read_history_t); + + return (0); +} + +static void +spa_read_history_init(spa_t *spa) +{ + spa_stats_history_t *ssh = &spa->spa_stats.read_history; + char name[KSTAT_STRLEN]; + kstat_t *ksp; + + mutex_init(&ssh->lock, NULL, MUTEX_DEFAULT, NULL); + list_create(&ssh->list, sizeof (spa_read_history_t), + offsetof(spa_read_history_t, srh_link)); + + ssh->count = 0; + ssh->size = 0; + ssh->private = NULL; + + (void) snprintf(name, KSTAT_STRLEN, "zfs/%s", spa_name(spa)); + name[KSTAT_STRLEN-1] = '\0'; + + ksp = kstat_create(name, 0, "reads", "misc", + KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL); + ssh->kstat = ksp; + + if (ksp) { + ksp->ks_lock = &ssh->lock; + ksp->ks_data = NULL; + ksp->ks_private = spa; + ksp->ks_update = spa_read_history_update; + kstat_set_raw_ops(ksp, spa_read_history_headers, + spa_read_history_data, spa_read_history_addr); + kstat_install(ksp); + } +} + +static void +spa_read_history_destroy(spa_t *spa) +{ + spa_stats_history_t *ssh = &spa->spa_stats.read_history; + spa_read_history_t *srh; + kstat_t *ksp; + + ksp = ssh->kstat; + if (ksp) + kstat_delete(ksp); + + mutex_enter(&ssh->lock); + while ((srh = list_remove_head(&ssh->list))) { + ssh->size--; + kmem_free(srh, sizeof(spa_read_history_t)); + } + + ASSERT3U(ssh->size, ==, 0); + list_destroy(&ssh->list); + mutex_exit(&ssh->lock); + + mutex_destroy(&ssh->lock); +} + +void +spa_read_history_add(spa_t *spa, const zbookmark_t *zb, uint32_t aflags) +{ + spa_stats_history_t *ssh = &spa->spa_stats.read_history; + spa_read_history_t *srh, *rm; + + ASSERT3P(spa, !=, NULL); + ASSERT3P(zb, !=, NULL); + + if (zfs_read_history == 0 && ssh->size == 0) + return; + + if (zfs_read_history_hits == 0 && (aflags & ARC_CACHED)) + return; + + srh = kmem_zalloc(sizeof(spa_read_history_t), KM_PUSHPAGE); + strlcpy(srh->origin, zb->zb_func, sizeof(srh->origin)); + strlcpy(srh->comm, getcomm(), sizeof(srh->comm)); + srh->start = gethrtime(); + srh->objset = zb->zb_objset; + srh->object = zb->zb_object; + srh->level = zb->zb_level; + srh->blkid = zb->zb_blkid; + srh->aflags = aflags; + srh->pid = getpid(); + + mutex_enter(&ssh->lock); + + srh->uid = ssh->count++; + list_insert_head(&ssh->list, srh); + ssh->size++; + + while (ssh->size > zfs_read_history) { + ssh->size--; + rm = list_remove_tail(&ssh->list); + kmem_free(rm, sizeof(spa_read_history_t)); + } + + mutex_exit(&ssh->lock); +} + +void +spa_stats_init(spa_t *spa) +{ + spa_read_history_init(spa); +} + +void +spa_stats_destroy(spa_t *spa) +{ + spa_read_history_destroy(spa); +} + +#if defined(_KERNEL) && defined(HAVE_SPL) +module_param(zfs_read_history, int, 0644); +MODULE_PARM_DESC(zfs_read_history, "Historic statistics for the last N reads"); + +module_param(zfs_read_history_hits, int, 0644); +MODULE_PARM_DESC(zfs_read_history_hits, "Include cache hits in read history"); +#endif |