svn commit: r342400 - head/sys/kern
Alexander Motin
mav at FreeBSD.org
Mon Dec 24 23:52:36 UTC 2018
Author: mav
Date: Mon Dec 24 23:52:35 2018
New Revision: 342400
URL: https://svnweb.freebsd.org/changeset/base/342400
Log:
Increase MTX_POOL_SLEEP_SIZE from 128 to 1024.
This value remained unchanged for 15 years, and now this bump reduces
lock spinning in GEOM and BIO layers while doing ~1.6M IOPS to 4 NVMe
on 72-core system from ~25% to ~5% by the cost of additional 28KB RAM.
While there, align struct mtx_pool fields to cache lines.
MFC after: 1 month
Modified:
head/sys/kern/kern_mtxpool.c
Modified: head/sys/kern/kern_mtxpool.c
==============================================================================
--- head/sys/kern/kern_mtxpool.c Mon Dec 24 23:28:11 2018 (r342399)
+++ head/sys/kern/kern_mtxpool.c Mon Dec 24 23:52:35 2018 (r342400)
@@ -62,14 +62,14 @@ static MALLOC_DEFINE(M_MTXPOOL, "mtx_pool", "mutex poo
/* Pool sizes must be a power of two */
#ifndef MTX_POOL_SLEEP_SIZE
-#define MTX_POOL_SLEEP_SIZE 128
+#define MTX_POOL_SLEEP_SIZE 1024
#endif
struct mtxpool_header {
int mtxpool_size;
int mtxpool_mask;
int mtxpool_shift;
- int mtxpool_next;
+ int mtxpool_next __aligned(CACHE_LINE_SIZE);
};
struct mtx_pool {
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