diff options
| author | Cyril Plisko <[email protected]> | 2014-01-15 11:26:12 +0200 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2014-01-23 13:31:51 -0800 |
| commit | 01b738f457f2a406fb6b4b264fb7a947b9b9989b (patch) | |
| tree | 6b31f68856959d4d499f365114ffdad79c172aeb | |
| parent | 478d64fdaeb89c8f029f3dd1969447317eedaa6e (diff) | |
Call gethrtime() only once per new txg creation
When transitioning current open TXG into QUIESCE state and opening
a new one txg_quiesce() calls gethrtime():
- to mark the birth time of the new TXG
- to record the SPA txg history kstat
- implicitely inside spa_txg_history_add()
These timestamps are practically the same, so that the first one
can be used instead of the other two. The only visible difference
is that inside spa_txg_history_add() the time spent in kmem_zalloc()
will be counted towards the opened TXG.
Since at this point the new TXG already exists (tx->tx_open_txg
has been already incremented) it is actually a correct accounting.
In any case this extra work is only happening when spa_txg_history
kstat is activated (i.e. zfs_txg_history > 0) and doesn't affect
the normal processing in any way.
Signed-off-by: Cyril Plisko <[email protected]>
Issue #2075
| -rw-r--r-- | include/sys/spa.h | 2 | ||||
| -rw-r--r-- | module/zfs/spa_stats.c | 4 | ||||
| -rw-r--r-- | module/zfs/txg.c | 4 |
3 files changed, 5 insertions, 5 deletions
diff --git a/include/sys/spa.h b/include/sys/spa.h index 0079c18fe..e7cbff806 100644 --- a/include/sys/spa.h +++ b/include/sys/spa.h @@ -566,7 +566,7 @@ extern void spa_stats_init(spa_t *spa); extern void spa_stats_destroy(spa_t *spa); extern void spa_read_history_add(spa_t *spa, const zbookmark_t *zb, uint32_t aflags); -extern void spa_txg_history_add(spa_t *spa, uint64_t txg); +extern void spa_txg_history_add(spa_t *spa, uint64_t txg, hrtime_t birth_time); extern int spa_txg_history_set(spa_t *spa, uint64_t txg, txg_state_t completed_state, hrtime_t completed_time); extern int spa_txg_history_set_io(spa_t *spa, uint64_t txg, uint64_t nread, diff --git a/module/zfs/spa_stats.c b/module/zfs/spa_stats.c index 2576d867f..a94fecfe8 100644 --- a/module/zfs/spa_stats.c +++ b/module/zfs/spa_stats.c @@ -422,7 +422,7 @@ spa_txg_history_destroy(spa_t *spa) * Add a new txg to historical record. */ void -spa_txg_history_add(spa_t *spa, uint64_t txg) +spa_txg_history_add(spa_t *spa, uint64_t txg, hrtime_t birth_time) { spa_stats_history_t *ssh = &spa->spa_stats.txg_history; spa_txg_history_t *sth, *rm; @@ -433,7 +433,7 @@ spa_txg_history_add(spa_t *spa, uint64_t txg) sth = kmem_zalloc(sizeof (spa_txg_history_t), KM_PUSHPAGE); sth->txg = txg; sth->state = TXG_STATE_OPEN; - sth->times[TXG_STATE_BIRTH] = gethrtime(); + sth->times[TXG_STATE_BIRTH] = birth_time; mutex_enter(&ssh->lock); diff --git a/module/zfs/txg.c b/module/zfs/txg.c index 89615a21a..9e9db9989 100644 --- a/module/zfs/txg.c +++ b/module/zfs/txg.c @@ -377,8 +377,8 @@ txg_quiesce(dsl_pool_t *dp, uint64_t txg) tx->tx_open_txg++; tx->tx_open_time = gethrtime(); - spa_txg_history_set(dp->dp_spa, txg, TXG_STATE_OPEN, gethrtime()); - spa_txg_history_add(dp->dp_spa, tx->tx_open_txg); + spa_txg_history_set(dp->dp_spa, txg, TXG_STATE_OPEN, tx->tx_open_time); + spa_txg_history_add(dp->dp_spa, tx->tx_open_txg, tx->tx_open_time); DTRACE_PROBE2(txg__quiescing, dsl_pool_t *, dp, uint64_t, txg); DTRACE_PROBE2(txg__opened, dsl_pool_t *, dp, uint64_t, tx->tx_open_txg); |