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authorPrakash Surya <[email protected]>2014-01-03 10:36:26 -0800
committerBrian Behlendorf <[email protected]>2014-02-21 16:10:49 -0800
commit624227854e619d1bf555445f3bc38730fb9278c4 (patch)
tree03139489a6b024a2a483523843a237ed60f9ecab /module
parentf521ce1b9c6102f9175f26548d4c521e115f8d60 (diff)
Disable arc_p adapt dampener by default
It's unclear why adjustments to arc_p need to be dampened as they are in arc_adjust. With that said, it's removal significantly improves the arc's ability to "warm up" to a given workload. Thus, I'm disabling by default until its usefulness is better understood. Signed-off-by: Prakash Surya <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #2110
Diffstat (limited to 'module')
-rw-r--r--module/zfs/arc.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index f66eaa407..68496783d 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -175,6 +175,9 @@ int zfs_arc_grow_retry = 5;
/* disable anon data aggressively growing arc_p */
int zfs_arc_p_aggressive_disable = 1;
+/* disable arc_p adapt dampener in arc_adapt */
+int zfs_arc_p_dampener_disable = 1;
+
/* log2(fraction of arc to reclaim) */
int zfs_arc_shrink_shift = 5;
@@ -2633,7 +2636,9 @@ arc_adapt(int bytes, arc_state_t *state)
if (state == arc_mru_ghost) {
mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ?
1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size));
- mult = MIN(mult, 10); /* avoid wild arc_p adjustment */
+
+ if (!zfs_arc_p_dampener_disable)
+ mult = MIN(mult, 10); /* avoid wild arc_p adjustment */
arc_p = MIN(arc_c, arc_p + bytes * mult);
} else if (state == arc_mfu_ghost) {
@@ -2641,7 +2646,9 @@ arc_adapt(int bytes, arc_state_t *state)
mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ?
1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size));
- mult = MIN(mult, 10);
+
+ if (!zfs_arc_p_dampener_disable)
+ mult = MIN(mult, 10);
delta = MIN(bytes * mult, arc_p);
arc_p = MAX(0, arc_p - delta);
@@ -5554,6 +5561,9 @@ MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size");
module_param(zfs_arc_p_aggressive_disable, int, 0644);
MODULE_PARM_DESC(zfs_arc_p_aggressive_disable, "disable aggressive arc_p grow");
+module_param(zfs_arc_p_dampener_disable, int, 0644);
+MODULE_PARM_DESC(zfs_arc_p_dampener_disable, "disable arc_p adapt dampener");
+
module_param(zfs_arc_shrink_shift, int, 0644);
MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)");