Reiserfs, Mongo and CPU question

Reiserfs, Mongo and CPU question

[Ricardo Galli]

Hans and reiserfs developers,
	the same student of my university
(http://www.cs.helsinki.fi/linux/linux-kernel/2001-18/0654.html) was
carrying up the mongo benchmarks against reiser, xfs, jfs and ext2 for
different base sizes.


For example, for the base size of 10.000 (the average of a clean
distribution is about 16.000 bytes) ReiserFS is even slower than ext2. I've
realised the bottleneck may be the CPU, a Cyrix MII 233MHz.

FSYS=ext2 FSYS=reiserfs

(time in sec.)
Create    32.72 / 56.90 = 0.58
Fragm.    1.49 / 2.22 = 0.67

Copy    98.53 / 131.81 = 0.75
Fragm.    1.49 / 2.26 = 0.66

Slinks    4.82 / 5.08 = 0.95
Read    187.90 / 299.23 = 0.63
Stats    1.01 / 0.99 = 1.02
Rename    2.40 / 2.23 = 1.08
Delete    6.55 / 4.82 = 1.36


Can you confirm it? We are going to do the same benchmarks on a PIII if you
think it's due to the cpu.

I don't post the URL of the benchmarks to the list because last time we were
slashdotted ;-) and we aren't convinced they are valueable, but I can send
it to you directly if you are interested.

Regards,

--
ricardo galli

Re: Reiserfs, Mongo and CPU question

[Chris Mason]

On Tuesday, May 15, 2001 01:41:01 PM +0200 Ricardo Galli <gallir@uib.es>
wrote:

> Hans and reiserfs developers,
> 	the same student of my university
> (http://www.cs.helsinki.fi/linux/linux-kernel/2001-18/0654.html) was
> carrying up the mongo benchmarks against reiser, xfs, jfs and ext2 for
> different base sizes.
> 
> 
> For example, for the base size of 10.000 (the average of a clean
> distribution is about 16.000 bytes) ReiserFS is even slower than ext2.
> I've realised the bottleneck may be the CPU, a Cyrix MII 233MHz.
> 

Would not surprise me, there's lots of room for improvement in reiserfs CPU
usage.  The 10k size is one of the worst cases for tail performance, those
numbers should increase if you mount with -o notail.

Here's a simple patch that should help on balance instensive apps (like
creates/deletes).  Please let me know if you see any difference with it.

-chris

diff -ur diff/linux/fs/reiserfs/fix_node.c linux/fs/reiserfs/fix_node.c
--- diff/linux/fs/reiserfs/fix_node.c	Mon Jan 15 18:31:19 2001
+++ linux/fs/reiserfs/fix_node.c	Fri Feb  2 15:40:54 2001
@@ -936,6 +936,7 @@
     if (p_s_tb->FEB[p_s_tb->cur_blknum])
       BUG();
 
+    mark_buffer_journal_new(p_s_new_bh) ;
     p_s_tb->FEB[p_s_tb->cur_blknum++] = p_s_new_bh;
   }