* Re: [PATCH *] vhand-2.1.65b released
[not found] <19971120152522.39483@helix.caltech.edu>
@ 1997-11-21 1:37 ` Rik van Riel
0 siblings, 0 replies; 3+ messages in thread
From: Rik van Riel @ 1997-11-21 1:37 UTC (permalink / raw)
To: Joe Fouche; +Cc: linux-mm
On Thu, 20 Nov 1997, Joe Fouche wrote:
> You wrote
> > since so many people have found something wrong with vhand-2.1.6[45]
> > (particularly the CPU usage), I have implemented their ideas and
> > I've made the 'anti-fragmentation' unit even more agressive, since
> > some people still reported crashes because of memory fragmentation...
>
> This one (65b) is really good. I also found that I could decrease the numbers
> in /proc/sys/vm/freepages (I had them set kind of high) to improve all-around
> interactive performance.
All-round performance is improved, but mostly on small-memory
machines... We still need to do some tuning and optimization
for special cases of memory usage (linear, directory scanning,
etc..).
>
> root 3 0.0 0.0 0 0 ? SW< 11:34 0:00 (kswapd)
> root 4 1.0 0.0 0 0 ? SW 11:34 2:16 (vhand)
See, the CPU usage is way to high. It might be OK for a 32Meg
system, but imagine someone trying this on a 512Meg system :)
Actually, someone with a 512Meg system agreed to try my patch
this weekend. If things go well the patch might be ready for
integration in the mainstream kernel...
> A good way to test vhand, then, might be to make freepages really high and watch
> as things get swapped out. :)
More importantly, does the system remain stable with an ultra-low
value of freepages?
>
> Wonder if the kernel could tune freepages automatically, based on some measure
> of the performance of swap devices? Maybe the same thing would apply to some of
> the numbers in struct swap_control_v5?
But of course it could. Setting the value of min_free_pages to the
average nr of pagefaults we had during the last time (weighed after
time...) could result in a smaller number of freepages when we don't
need them, and increase the number of freepages when we need the
memory most. Hmm, I gotta try this one.
>
> Anyway, send it to Linus, it works great! :)
It works great for US, small-memory users. But there are also
those people around who have large (> 64M) memory systems. I
won't send it to Linus unless I know it works _flawlessly_ on
large-memory systems as well.
Rik.
----------
Send Linux memory-management wishes to me: I'm currently looking
for something to hack...
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