From eb9bec0a5d19abf9404f52081424fbb814e6188a 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 adb00f1c8..da1aa9c34 100644 --- a/man/man4/zfs.4 +++ b/man/man4/zfs.4 @@ -1677,7 +1677,7 @@ 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 ba9224777..3bf08fbdc 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -70,7 +70,7 @@ static int zfs_nopwrite_enabled = 1; * will wait until the next TXG. * A value of zero will disable this throttle. */ -static unsigned long zfs_per_txg_dirty_frees_percent = 5; +static unsigned long zfs_per_txg_dirty_frees_percent = 30; /* * Enable/disable forcing txg sync when dirty checking for holes with lseek().