diff --git a/include/sys/zil_impl.h b/include/sys/zil_impl.h index f780ad3d6..c9db6d428 100644 --- a/include/sys/zil_impl.h +++ b/include/sys/zil_impl.h @@ -181,6 +181,7 @@ typedef struct zil_vdev_node { avl_node_t zv_node; /* AVL tree linkage */ } zil_vdev_node_t; +#define ZIL_BURSTS 8 #define ZIL_PREV_BLKS 16 /* @@ -222,8 +223,9 @@ struct zilog { clock_t zl_replay_time; /* lbolt of when replay started */ uint64_t zl_replay_blks; /* number of log blocks replayed */ zil_header_t zl_old_header; /* debugging aid */ - uint_t zl_prev_blks[ZIL_PREV_BLKS]; /* size - sector rounded */ + uint_t zl_parallel; /* workload is multi-threaded */ uint_t zl_prev_rotor; /* rotor for zl_prev[] */ + uint_t zl_prev_blks[ZIL_PREV_BLKS]; /* size - sector rounded */ txg_node_t zl_dirty_link; /* protected by dp_dirty_zilogs list */ uint64_t zl_dirty_max_txg; /* highest txg used to dirty zilog */ diff --git a/man/man4/zfs.4 b/man/man4/zfs.4 index bab40dd91..5307f1f32 100644 --- a/man/man4/zfs.4 +++ b/man/man4/zfs.4 @@ -799,7 +799,7 @@ Note that this should not be set below the ZED thresholds (currently 10 checksums over 10 seconds) or else the daemon may not trigger any action. . -.It Sy zfs_commit_timeout_pct Ns = Ns Sy 5 Ns % Pq uint +.It Sy zfs_commit_timeout_pct Ns = Ns Sy 10 Ns % Pq uint This controls the amount of time that a ZIL block (lwb) will remain "open" when it isn't "full", and it has a thread waiting for it to be committed to stable storage. @@ -2206,13 +2206,6 @@ This sets the maximum number of write bytes logged via WR_COPIED. It tunes a tradeoff between additional memory copy and possibly worse log space efficiency vs additional range lock/unlock. . -.It Sy zil_min_commit_timeout Ns = Ns Sy 5000 Pq u64 -This sets the minimum delay in nanoseconds ZIL care to delay block commit, -waiting for more records. -If ZIL writes are too fast, kernel may not be able sleep for so short interval, -increasing log latency above allowed by -.Sy zfs_commit_timeout_pct . -. .It Sy zil_nocacheflush Ns = Ns Sy 0 Ns | Ns 1 Pq int Disable the cache flush commands that are normally sent to disk by the ZIL after an LWB write has completed. diff --git a/module/zfs/zil.c b/module/zfs/zil.c index 5642f082b..8742fc662 100644 --- a/module/zfs/zil.c +++ b/module/zfs/zil.c @@ -91,15 +91,7 @@ * committed to stable storage. Please refer to the zil_commit_waiter() * function (and the comments within it) for more details. */ -static uint_t zfs_commit_timeout_pct = 5; - -/* - * Minimal time we care to delay commit waiting for more ZIL records. - * At least FreeBSD kernel can't sleep for less than 2us at its best. - * So requests to sleep for less then 5us is a waste of CPU time with - * a risk of significant log latency increase due to oversleep. - */ -static uint64_t zil_min_commit_timeout = 5000; +static uint_t zfs_commit_timeout_pct = 10; /* * See zil.h for more information about these fields. @@ -2732,6 +2724,19 @@ zil_commit_writer_stall(zilog_t *zilog) ASSERT(list_is_empty(&zilog->zl_lwb_list)); } +static void +zil_burst_done(zilog_t *zilog) +{ + if (!list_is_empty(&zilog->zl_itx_commit_list) || + zilog->zl_cur_used == 0) + return; + + if (zilog->zl_parallel) + zilog->zl_parallel--; + + zilog->zl_cur_used = 0; +} + /* * This function will traverse the commit list, creating new lwbs as * needed, and committing the itxs from the commit list to these newly @@ -2746,7 +2751,6 @@ zil_process_commit_list(zilog_t *zilog, zil_commit_waiter_t *zcw, list_t *ilwbs) list_t nolwb_waiters; lwb_t *lwb, *plwb; itx_t *itx; - boolean_t first = B_TRUE; ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); @@ -2772,9 +2776,22 @@ zil_process_commit_list(zilog_t *zilog, zil_commit_waiter_t *zcw, list_t *ilwbs) zil_commit_activate_saxattr_feature(zilog); ASSERT(lwb->lwb_state == LWB_STATE_NEW || lwb->lwb_state == LWB_STATE_OPENED); - first = (lwb->lwb_state == LWB_STATE_NEW) && - ((plwb = list_prev(&zilog->zl_lwb_list, lwb)) == NULL || - plwb->lwb_state == LWB_STATE_FLUSH_DONE); + + /* + * If the lwb is still opened, it means the workload is really + * multi-threaded and we won the chance of write aggregation. + * If it is not opened yet, but previous lwb is still not + * flushed, it still means the workload is multi-threaded, but + * there was too much time between the commits to aggregate, so + * we try aggregation next times, but without too much hopes. + */ + if (lwb->lwb_state == LWB_STATE_OPENED) { + zilog->zl_parallel = ZIL_BURSTS; + } else if ((plwb = list_prev(&zilog->zl_lwb_list, lwb)) + != NULL && plwb->lwb_state != LWB_STATE_FLUSH_DONE) { + zilog->zl_parallel = MAX(zilog->zl_parallel, + ZIL_BURSTS / 2); + } } while ((itx = list_remove_head(&zilog->zl_itx_commit_list)) != NULL) { @@ -2849,7 +2866,7 @@ zil_process_commit_list(zilog_t *zilog, zil_commit_waiter_t *zcw, list_t *ilwbs) * Our lwb is done, leave the rest of * itx list to somebody else who care. */ - first = B_FALSE; + zilog->zl_parallel = ZIL_BURSTS; break; } } else { @@ -2941,28 +2958,15 @@ zil_process_commit_list(zilog_t *zilog, zil_commit_waiter_t *zcw, list_t *ilwbs) * try and pack as many itxs into as few lwbs as * possible, without significantly impacting the latency * of each individual itx. - * - * If we had no already running or open LWBs, it can be - * the workload is single-threaded. And if the ZIL write - * latency is very small or if the LWB is almost full, it - * may be cheaper to bypass the delay. */ - if (lwb->lwb_state == LWB_STATE_OPENED && first) { - hrtime_t sleep = zilog->zl_last_lwb_latency * - zfs_commit_timeout_pct / 100; - if (sleep < zil_min_commit_timeout || - lwb->lwb_nmax - lwb->lwb_nused < - lwb->lwb_nmax / 8) { - list_insert_tail(ilwbs, lwb); - lwb = zil_lwb_write_close(zilog, lwb, - LWB_STATE_NEW); - zilog->zl_cur_used = 0; - if (lwb == NULL) { - while ((lwb = list_remove_head(ilwbs)) - != NULL) - zil_lwb_write_issue(zilog, lwb); - zil_commit_writer_stall(zilog); - } + if (lwb->lwb_state == LWB_STATE_OPENED && !zilog->zl_parallel) { + list_insert_tail(ilwbs, lwb); + lwb = zil_lwb_write_close(zilog, lwb, LWB_STATE_NEW); + zil_burst_done(zilog); + if (lwb == NULL) { + while ((lwb = list_remove_head(ilwbs)) != NULL) + zil_lwb_write_issue(zilog, lwb); + zil_commit_writer_stall(zilog); } } } @@ -3120,19 +3124,7 @@ zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw) ASSERT3S(lwb->lwb_state, ==, LWB_STATE_CLOSED); - /* - * Since the lwb's zio hadn't been issued by the time this thread - * reached its timeout, we reset the zilog's "zl_cur_used" field - * to influence the zil block size selection algorithm. - * - * By having to issue the lwb's zio here, it means the size of the - * lwb was too large, given the incoming throughput of itxs. By - * setting "zl_cur_used" to zero, we communicate this fact to the - * block size selection algorithm, so it can take this information - * into account, and potentially select a smaller size for the - * next lwb block that is allocated. - */ - zilog->zl_cur_used = 0; + zil_burst_done(zilog); if (nlwb == NULL) { /* @@ -4250,9 +4242,6 @@ EXPORT_SYMBOL(zil_kstat_values_update); ZFS_MODULE_PARAM(zfs, zfs_, commit_timeout_pct, UINT, ZMOD_RW, "ZIL block open timeout percentage"); -ZFS_MODULE_PARAM(zfs_zil, zil_, min_commit_timeout, U64, ZMOD_RW, - "Minimum delay we care for ZIL block commit"); - ZFS_MODULE_PARAM(zfs_zil, zil_, replay_disable, INT, ZMOD_RW, "Disable intent logging replay");