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authorMark Fasheh <mfasheh@suse.com>2010-04-06 05:17:14 +0400
committerJoel Becker <joel.becker@oracle.com>2010-05-06 05:18:07 +0400
commit6b82021b9e91cd689fdffadbcdb9a42597bbe764 (patch)
treeac4235e792e74a2e60a41e95d62965b7ed4b3232 /fs/ocfs2/ocfs2_fs.h
parent73c8a80003d13be54e2309865030404441075182 (diff)
downloadlinux-6b82021b9e91cd689fdffadbcdb9a42597bbe764.tar.xz
ocfs2: increase the default size of local alloc windows
I have observed that the current size of 8M gives us pretty poor fragmentation on multi-threaded workloads which do lots of writes. Generally, I can increase the size of local alloc windows and observe a marked decrease in fragmentation, even up and beyond window sizes of 512 megabytes. This makes sense for a couple reasons - larger local alloc means more room for reservation windows. On multi-node workloads the larger local alloc helps as well because we don't have to do window slides as often. Also, I removed the OCFS2_DEFAULT_LOCAL_ALLOC_SIZE constant as it is no longer used and the comment above it was out of date. To test fragmentation, I used a workload which launched 4 threads that did 4k writes into a series of about 140 alternating files. With resv_level=2, and a 4k/4k file system I observed the following average fragmentation for various localalloc= parameters: localalloc= avg. fragmentation 8 48 32 16 64 10 120 7 On larger cluster sizes, the difference is more dramatic. The new default size top out at 256M, which we'll only get for cluster sizes of 32K and above. Signed-off-by: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/ocfs2/ocfs2_fs.h')
-rw-r--r--fs/ocfs2/ocfs2_fs.h8
1 files changed, 0 insertions, 8 deletions
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index bb37218a7978..d61a1521b10e 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -283,14 +283,6 @@
#define OCFS2_MIN_JOURNAL_SIZE (4 * 1024 * 1024)
/*
- * Default local alloc size (in megabytes)
- *
- * The value chosen should be such that most allocations, including new
- * block groups, use local alloc.
- */
-#define OCFS2_DEFAULT_LOCAL_ALLOC_SIZE 8
-
-/*
* Inline extended attribute size (in bytes)
* The value chosen should be aligned to 16 byte boundaries.
*/