[patch] speed up ext3 synchronous mounts

[patch] speed up ext3 synchronous mounts

[Andrew Morton]

Again, we don't need to sync indirects as we dirty them because
we run a commit if IS_SYNC(inode) prior to returning to the
caller of write(2).

Writing a 10 meg file in 0.1 meg chunks is sped up by, err,
a factor of fifty.  That's a best case.

--- linux-2.4.18-pre8/fs/ext3/inode.c	Tue Feb  5 00:33:05 2002
+++ linux-akpm/fs/ext3/inode.c	Wed Feb  6 23:40:48 2002
@@ -581,8 +581,6 @@ static int ext3_alloc_branch(handle_t *h
 			
 			parent = nr;
 		}
-		if (IS_SYNC(inode))
-			handle->h_sync = 1;
 	}
 	if (n == num)
 		return 0;


-

Re: [Ext2-devel] [patch] speed up ext3 synchronous mounts

[Stephen C. Tweedie]

Hi,

On Sun, Mar 24, 2002 at 01:50:16PM -0800, Andrew Morton wrote:
 
> Again, we don't need to sync indirects as we dirty them because
> we run a commit if IS_SYNC(inode) prior to returning to the
> caller of write(2).
> 
> Writing a 10 meg file in 0.1 meg chunks is sped up by, err,
> a factor of fifty.  That's a best case.
> 
> --- linux-2.4.18-pre8/fs/ext3/inode.c	Tue Feb  5 00:33:05 2002
> +++ linux-akpm/fs/ext3/inode.c	Wed Feb  6 23:40:48 2002
> @@ -581,8 +581,6 @@ static int ext3_alloc_branch(handle_t *h
>  			
>  			parent = nr;
>  		}
> -		if (IS_SYNC(inode))
> -			handle->h_sync = 1;
>  	}
>  	if (n == num)
>  		return 0;

OK.  This was just a relic of ages back when we had an overarching
transaction spanning multiple writepages in ext3_file_write().  In
that case, setting that transaction to be synchronous multiple times
was no extra cost.  Doing it just once at the end should be fine.

Cheers,
 Stephen

Re: [patch] speed up ext3 synchronous mounts

[Matthias Andree]

On Sun, 24 Mar 2002, Andrew Morton wrote:

> Again, we don't need to sync indirects as we dirty them because
> we run a commit if IS_SYNC(inode) prior to returning to the
> caller of write(2).

Will this help synchronous NFS writes, at least a little? I have slow
write performance on "sync" NFSv3 exports (ext3 underneath, you guessed
it), kernel 2.4.19-pre3-ac4 (not really surprising, sync is slow ;-). Is
it worth a try?

Re: [patch] speed up ext3 synchronous mounts

[Ed Sweetman]

On Wed, 2002-03-27 at 14:07, Matthias Andree wrote:
> On Sun, 24 Mar 2002, Andrew Morton wrote:
> 
> > Again, we don't need to sync indirects as we dirty them because
> > we run a commit if IS_SYNC(inode) prior to returning to the
> > caller of write(2).
> 
> Will this help synchronous NFS writes, at least a little? I have slow
> write performance on "sync" NFSv3 exports (ext3 underneath, you guessed
> it), kernel 2.4.19-pre3-ac4 (not really surprising, sync is slow ;-). Is
> it worth a try?

if you look at the source.  that kernel doesn't need the patch. Seems to
have already been applied since ac1


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Re: [patch] speed up ext3 synchronous mounts

[Andreas Dilger]

On Mar 27, 2002  20:07 +0100, Matthias Andree wrote:
> On Sun, 24 Mar 2002, Andrew Morton wrote:
> > Again, we don't need to sync indirects as we dirty them because
> > we run a commit if IS_SYNC(inode) prior to returning to the
> > caller of write(2).
> 
> Will this help synchronous NFS writes, at least a little? I have slow
> write performance on "sync" NFSv3 exports (ext3 underneath, you guessed
> it), kernel 2.4.19-pre3-ac4 (not really surprising, sync is slow ;-). Is
> it worth a try?

Are you mounting the ext3 filesystem with "data=journal" and have a
large journal?  This will help a lot.  You can also set up an external
journal device to speed things up.

Cheers, Andreas
--
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert