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SubjectRe: [Lockmeter 2.5] BKL with 51ms hold time, prove me wrong
--On Thursday, April 10, 2003 06:50:06 PM -0700 Andrew Morton <akpm@digeo.com> wrote:

> I'm a bit surprised that even slow machine like that would take 50
> milliseconds to truncate 128MB of file, but it's not impossible I guess.
> Truncate is not really a fastpath. ext3 in -mm doesn't have any lock_kernels
> in it.

Sure enough. I ported lockmeter to 2.5.67-mm1 and ran the same rmap-test
and lo and behold all the ext3 issues went away. However, the one remaining
long hold time moved to the top (unmap_vmas):
___________________________________________________________________________________________
System: Linux w-hlinder2 2.5.67-mm1 #1 SMP Fri Apr 11 12:31:38 PDT 2003 i686

SPINLOCKS HOLD WAIT
UTIL CON MEAN( MAX ) MEAN( MAX )(% CPU) TOTAL NOWAIT SPIN RJECT NAME

19.2% 2.0us( 49ms) 1.1us(9767us)(0.58%) 5506902 80.8% 16.6% 2.5% *TOTAL*

0.30% 0.00% 0.4us(9728us) 2598us(3751us)(0.01%) 672210 100% 0.00% 0% journal_datalist_lock

0.26% 0.01% 1.1us(9759us) 4116us(9767us)(0.04%) 211510 100% 0.01% 0% kernel_flag

0.00% 10.9% 2.2us( 14us) 1.0us( 1.9us)(0.00%) 137 89.1% 10.9% 0% runqueues
0.00% 42.9% 1.6us( 14us) 1.0us( 1.9us)(0.00%) 35 57.1% 42.9% 0% load_balance+0x138
0.00% 0% 2.3us( 3.9us) 0us 102 100% 0% 0% wake_up_forked_process+0x3c

3.1% 0% 11ms( 49ms) 0us 245 100% 0% 0% unmap_vmas+0x1c0

------------

Here is the port of lockmeter to the 2.5.67-mm1 kernel. If you would consider
putting it in your tree that would be great and I would work on porting the
rest of the architectures.

http://prdownloads.sourceforge.net/lse/lockmeter1.5-2.5.67-mm1.patch?download

Here is also the whole locmeter output of this run if
you are interested.

http://prdownloads.sourceforge.net/lse/lockstat-mm1.rmapm?download

Thanks a lot!

Hanna Linder
IBM Linux Technology Center
hannal@us.ibm.com




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