From c8d6a91a993c6e5da47ba24d52e6f01bf3a0e01f Mon Sep 17 00:00:00 2001 From: Mateusz Guzik Date: Wed, 28 Sep 2022 02:38:03 +0200 Subject: [PATCH] Bring per_txg_dirty_frees_percent back to 30 The current value causes significant artificial slowdown during mass parallel file removal, which can be observed both on FreeBSD and Linux when running real workloads. Sample results from Linux doing make -j 96 clean after an allyesconfig modules build: before: 4.14s user 6.79s system 48% cpu 22.631 total after: 4.17s user 6.44s system 153% cpu 6.927 total FreeBSD results in the ticket. Reviewed-by: Alexander Motin Reviewed-by: Brian Behlendorf Reviewed-by: Richard Yao Reviewed-by: George Melikov Signed-off-by: Mateusz Guzik Closes #13932 Closes #13938 --- man/man4/zfs.4 | 2 +- module/zfs/dmu.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/man/man4/zfs.4 b/man/man4/zfs.4 index fcb97d716d..b317941bbd 100644 --- a/man/man4/zfs.4 +++ b/man/man4/zfs.4 @@ -1651,7 +1651,7 @@ prefetched during a pool traversal, like .Nm zfs Cm send or other data crawling operations. . -.It Sy zfs_per_txg_dirty_frees_percent Ns = Ns Sy 5 Ns % Pq ulong +.It Sy zfs_per_txg_dirty_frees_percent Ns = Ns Sy 30 Ns % Pq ulong Control percentage of dirtied indirect blocks from frees allowed into one TXG. After this threshold is crossed, additional frees will wait until the next TXG. .Sy 0 No disables this throttle. diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c index 0832fbcfdf..c67a36470e 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -71,7 +71,7 @@ int zfs_nopwrite_enabled = 1; * will wait until the next TXG. * A value of zero will disable this throttle. */ -unsigned long zfs_per_txg_dirty_frees_percent = 5; +unsigned long zfs_per_txg_dirty_frees_percent = 30; /* * Enable/disable forcing txg sync when dirty checking for holes with lseek().