From b654aad6c8a7f28f90c8dcb4237432d525d8e46b Mon Sep 17 00:00:00 2001 From: Tony Nguyen Date: Mon, 12 Aug 2019 14:58:59 -0600 Subject: [PATCH] Improve write performance by using dmu_read_by_dnode() In zfs_log_write(), we can use dmu_read_by_dnode() rather than dmu_read() thus avoiding unnecessary dnode_hold() calls. We get a 2-5% performance gain for large sequential_writes tests, >=128K writes to files with recordsize=8K. Testing done on Ubuntu 18.04 with 4.15 kernel, 8vCPUs and SSD storage on VMware ESX. Signed-off-by: Tony Nguyen --- module/zfs/zfs_log.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/module/zfs/zfs_log.c b/module/zfs/zfs_log.c index ad5b5cf30b1e..b8dae8f40fb5 100644 --- a/module/zfs/zfs_log.c +++ b/module/zfs/zfs_log.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include #include @@ -497,6 +498,7 @@ zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype, znode_t *zp, offset_t off, ssize_t resid, int ioflag, zil_callback_t callback, void *callback_data) { + dmu_buf_impl_t *db = (dmu_buf_impl_t *)sa_get_db(zp->z_sa_hdl); uint32_t blocksize = zp->z_blksz; itx_wr_state_t write_state; uintptr_t fsync_cnt; @@ -543,13 +545,16 @@ zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype, itx = zil_itx_create(txtype, sizeof (*lr) + (wr_state == WR_COPIED ? len : 0)); lr = (lr_write_t *)&itx->itx_lr; - if (wr_state == WR_COPIED && dmu_read(ZTOZSB(zp)->z_os, - zp->z_id, off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) { + + DB_DNODE_ENTER(db); + if (wr_state == WR_COPIED && dmu_read_by_dnode(DB_DNODE(db), + off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) { zil_itx_destroy(itx); itx = zil_itx_create(txtype, sizeof (*lr)); lr = (lr_write_t *)&itx->itx_lr; wr_state = WR_NEED_COPY; } + DB_DNODE_EXIT(db); itx->itx_wr_state = wr_state; lr->lr_foid = zp->z_id;