Chris Mason wrote:
On Fri, Aug 06, 2010 at 01:44:11PM -0500, Steven Pratt wrote:
Here is the latest set of performance runs from the 2.6.35-rc5 tree.
Included is a refresh of all the other filesystems with some changes
for barriers on and off since this has been somewhat of a hot topic
recently.
New data linked in to the history graphs here:
http://btrfs.boxacle.net/repository/raid/history/History.html
From a BTRFS performance perspective, we took a major regression on
write heavy workloads. As much as a 10x hit! The problems seems to
be due to this changeset:
http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-unstable.git;a=commit;h=5da9d01b66458b180a6bee0e637a1d0a3effc622
Btrfs: Shrink delay allocated space in a synchronized
Shrink delayed allocation space in a synchronized manner is more
controllable than flushing all delay allocated space in an async
thread.
This changeset introduced "btrfs_start_one_delalloc_inode" in
http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-unstable.git;a=commitdiff;h=5da9d01b66458b180a6bee0e637a1d0a3effc622
In heavy write workloads this new function is now dominating the profiles:
samples % app name symbol name
8914973 65.1261 btrfs.ko btrfs_start_one_delalloc_inode
Hi Steve,
I think I know why this is a problem and how to fix it, but I'm having a
trouble reproducing this exact setup. Which of your tests was this
oprofile from?
128 thread random write. With or without nocow option.
Steve
-chris
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
