From 478d64fdaeb89c8f029f3dd1969447317eedaa6e Mon Sep 17 00:00:00 2001 From: Igor Lvovsky Date: Thu, 16 Jan 2014 11:41:27 +0200 Subject: [PATCH] Add additional state TXG_STATE_WAIT_FOR_SYNC for txg. In several cases when digging into kstats we can found two txgs in SYNC state, e.g. txg birth state nreserved nread nwritten ... 985452 258127184872561 C 0 373948416 2376272384 ... 985453 258129016180616 C 0 378173440 28793344 ... 985454 258129016271523 S 0 0 0 ... 985455 258130864245986 S 0 0 0 ... 985456 258130867458851 O 0 0 0 ... However only first txg (985454) is really syncing at this moment. The other one (985455) marked as SYNCED is actually in a post-QUIESCED state and waiting to start sync. So, the new TXG_STATE_WAIT_FOR_SYNC state between TXG_STATE_QUIESCED and TXG_STATE_SYNCED was added to reveal this situation. txg birth state nreserved nread nwritten ... 1086896 235261068743969 C 0 163577856 8437248 ... 1086897 235262870830801 C 0 280625152 822594048 ... 1086898 235264172219064 S 0 0 0 ... 1086899 235264936134407 W 0 0 0 ... 1086900 235264936296156 O 0 0 0 ... Signed-off-by: Igor Lvovsky Signed-off-by: Brian Behlendorf Issue #2075 --- include/sys/spa.h | 5 +++-- module/zfs/spa_stats.c | 20 +++++++++++++------- module/zfs/txg.c | 3 +++ 3 files changed, 19 insertions(+), 9 deletions(-) diff --git a/include/sys/spa.h b/include/sys/spa.h index 13c9672aadb6..0079c18fea34 100644 --- a/include/sys/spa.h +++ b/include/sys/spa.h @@ -557,8 +557,9 @@ typedef enum txg_state { TXG_STATE_BIRTH = 0, TXG_STATE_OPEN = 1, TXG_STATE_QUIESCED = 2, - TXG_STATE_SYNCED = 3, - TXG_STATE_COMMITTED = 4, + TXG_STATE_WAIT_FOR_SYNC = 3, + TXG_STATE_SYNCED = 4, + TXG_STATE_COMMITTED = 5, } txg_state_t; extern void spa_stats_init(spa_t *spa); diff --git a/module/zfs/spa_stats.c b/module/zfs/spa_stats.c index c415395f9803..2576d867fb92 100644 --- a/module/zfs/spa_stats.c +++ b/module/zfs/spa_stats.c @@ -258,9 +258,9 @@ static int spa_txg_history_headers(char *buf, size_t size) { size = snprintf(buf, size - 1, "%-8s %-16s %-5s %-12s %-12s %-12s " - "%-8s %-8s %-12s %-12s %-12s\n", "txg", "birth", "state", + "%-8s %-8s %-12s %-12s %-12s %-12s\n", "txg", "birth", "state", "nreserved", "nread", "nwritten", "reads", "writes", - "otime", "qtime", "stime"); + "otime", "qtime", "wtime", "stime"); buf[size] = '\0'; return (0); @@ -270,13 +270,14 @@ static int spa_txg_history_data(char *buf, size_t size, void *data) { spa_txg_history_t *sth = (spa_txg_history_t *)data; - uint64_t open = 0, quiesce = 0, sync = 0; + uint64_t open = 0, quiesce = 0, wait = 0, sync = 0; char state; switch (sth->state) { case TXG_STATE_BIRTH: state = 'B'; break; case TXG_STATE_OPEN: state = 'O'; break; case TXG_STATE_QUIESCED: state = 'Q'; break; + case TXG_STATE_WAIT_FOR_SYNC: state = 'W'; break; case TXG_STATE_SYNCED: state = 'S'; break; case TXG_STATE_COMMITTED: state = 'C'; break; default: state = '?'; break; @@ -290,17 +291,22 @@ spa_txg_history_data(char *buf, size_t size, void *data) quiesce = sth->times[TXG_STATE_QUIESCED] - sth->times[TXG_STATE_OPEN]; - if (sth->times[TXG_STATE_SYNCED]) - sync = sth->times[TXG_STATE_SYNCED] - + if (sth->times[TXG_STATE_WAIT_FOR_SYNC]) + wait = sth->times[TXG_STATE_WAIT_FOR_SYNC] - sth->times[TXG_STATE_QUIESCED]; + if (sth->times[TXG_STATE_SYNCED]) + sync = sth->times[TXG_STATE_SYNCED] - + sth->times[TXG_STATE_WAIT_FOR_SYNC]; + size = snprintf(buf, size - 1, "%-8llu %-16llu %-5c %-12llu " - "%-12llu %-12llu %-8llu %-8llu %-12llu %-12llu %-12llu\n", + "%-12llu %-12llu %-8llu %-8llu %-12llu %-12llu %-12llu %-12llu\n", (longlong_t)sth->txg, sth->times[TXG_STATE_BIRTH], state, (u_longlong_t)sth->nreserved, (u_longlong_t)sth->nread, (u_longlong_t)sth->nwritten, (u_longlong_t)sth->reads, (u_longlong_t)sth->writes, - (u_longlong_t)open, (u_longlong_t)quiesce, (u_longlong_t)sync); + (u_longlong_t)open, (u_longlong_t)quiesce, (u_longlong_t)wait, + (u_longlong_t)sync); buf[size] = '\0'; return (0); diff --git a/module/zfs/txg.c b/module/zfs/txg.c index c779c4b9a28a..89615a21a404 100644 --- a/module/zfs/txg.c +++ b/module/zfs/txg.c @@ -555,6 +555,9 @@ txg_sync_thread(dsl_pool_t *dp) txg, tx->tx_quiesce_txg_waiting, tx->tx_sync_txg_waiting); mutex_exit(&tx->tx_sync_lock); + spa_txg_history_set(spa, txg, TXG_STATE_WAIT_FOR_SYNC, + gethrtime()); + start = ddi_get_lbolt(); spa_sync(spa, txg); delta = ddi_get_lbolt() - start;