MFV r274271:

Improve zdb -b performance:

 - Reduce gethrtime() call to 1/100th of blkptr's;
 - Skip manipulating the size-ordered tree;
 - Issue more (10, previously 3) async reads;
 - Use lighter weight testing in traverse_visitbp();

Illumos issue:
    5243 zdb -b could be much faster

MFC after:	2 weeks
This commit is contained in:
Xin LI 2014-11-08 07:30:40 +00:00
commit 81f1255e58
2 changed files with 47 additions and 21 deletions

View File

@ -77,9 +77,11 @@
#ifndef lint
extern boolean_t zfs_recover;
extern uint64_t zfs_arc_max, zfs_arc_meta_limit;
extern int zfs_vdev_async_read_max_active;
#else
boolean_t zfs_recover;
uint64_t zfs_arc_max, zfs_arc_meta_limit;
int zfs_vdev_async_read_max_active;
#endif
const char cmdname[] = "zdb";
@ -2384,8 +2386,14 @@ zdb_blkptr_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
zcb->zcb_readfails = 0;
if (dump_opt['b'] < 5 &&
gethrtime() > zcb->zcb_lastprint + NANOSEC) {
/* only call gethrtime() every 100 blocks */
static int iters;
if (++iters > 100)
iters = 0;
else
return (0);
if (dump_opt['b'] < 5 && gethrtime() > zcb->zcb_lastprint + NANOSEC) {
uint64_t now = gethrtime();
char buf[10];
uint64_t bytes = zcb->zcb_type[ZB_TOTAL][ZDB_OT_TOTAL].zb_asize;
@ -2494,6 +2502,14 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb)
(longlong_t)vd->vdev_ms_count);
msp->ms_ops = &zdb_metaslab_ops;
/*
* We don't want to spend the CPU
* manipulating the size-ordered
* tree, so clear the range_tree
* ops.
*/
msp->ms_tree->rt_ops = NULL;
VERIFY0(space_map_load(msp->ms_sm,
msp->ms_tree, SM_ALLOC));
msp->ms_loaded = B_TRUE;
@ -3508,6 +3524,13 @@ main(int argc, char **argv)
*/
zfs_arc_max = zfs_arc_meta_limit = 256 * 1024 * 1024;
/*
* "zdb -c" uses checksum-verifying scrub i/os which are async reads.
* "zdb -b" uses traversal prefetch which uses async reads.
* For good performance, let several of them be active at once.
*/
zfs_vdev_async_read_max_active = 10;
kernel_init(FREAD);
g_zfs = libzfs_init();
ASSERT(g_zfs != NULL);

View File

@ -59,6 +59,7 @@ typedef struct traverse_data {
int td_flags;
prefetch_data_t *td_pfd;
boolean_t td_paused;
uint64_t td_hole_birth_enabled_txg;
blkptr_cb_t *td_func;
void *td_arg;
} traverse_data_t;
@ -229,25 +230,20 @@ traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
}
if (bp->blk_birth == 0) {
if (spa_feature_is_active(td->td_spa, SPA_FEATURE_HOLE_BIRTH)) {
/*
* Since this block has a birth time of 0 it must be a
* hole created before the SPA_FEATURE_HOLE_BIRTH
* feature was enabled. If SPA_FEATURE_HOLE_BIRTH
* was enabled before the min_txg for this traveral we
* know the hole must have been created before the
* min_txg for this traveral, so we can skip it. If
* SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg
* for this traveral we cannot tell if the hole was
* created before or after the min_txg for this
* traversal, so we cannot skip it.
*/
uint64_t hole_birth_enabled_txg;
VERIFY(spa_feature_enabled_txg(td->td_spa,
SPA_FEATURE_HOLE_BIRTH, &hole_birth_enabled_txg));
if (hole_birth_enabled_txg < td->td_min_txg)
return (0);
}
/*
* Since this block has a birth time of 0 it must be a
* hole created before the SPA_FEATURE_HOLE_BIRTH
* feature was enabled. If SPA_FEATURE_HOLE_BIRTH
* was enabled before the min_txg for this traveral we
* know the hole must have been created before the
* min_txg for this traveral, so we can skip it. If
* SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg
* for this traveral we cannot tell if the hole was
* created before or after the min_txg for this
* traversal, so we cannot skip it.
*/
if (td->td_hole_birth_enabled_txg < td->td_min_txg)
return (0);
} else if (bp->blk_birth <= td->td_min_txg) {
return (0);
}
@ -523,6 +519,13 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
td.td_flags = flags;
td.td_paused = B_FALSE;
if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
VERIFY(spa_feature_enabled_txg(spa,
SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg));
} else {
td.td_hole_birth_enabled_txg = 0;
}
pd.pd_blks_max = zfs_pd_blks_max;
pd.pd_flags = flags;
mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);