Re: [PATCH 00/25] Vm Pageout Scalability Improvements (V8) - continued

["John Stoffel" <john@stoffel.org>]

Rik> On Fri, 30 May 2008 09:52:48 -0400
Rik> "John Stoffel" <john@stoffel.org> wrote:

>> I haven't seen any performance numbers talking about how well this
>> stuff works on single or dual CPU machines with smaller amounts of
>> memory, or whether it's worth using on these machines at all?
>> 
>> The big machines with lots of memory and lots of CPUs are certainly
>> becoming more prevalent, but for my home machine with 4Gb RAM and dual
>> core, what's the advantage?  
>> 
>> Let's not slow down the common case for the sake of the bigger guys if
>> possible.

Rik> I wouldn't call your home system with 4GB RAM "small".

*grin* me either in some ways.  But my other main linux box, which
acts as an NFS server has 2Gb of RAM, but a pair of PIII Xeons at
550mhz.  This is the box I'd be worried about in some ways, since it
handles a bunch of stuff like backups, mysql, apache, NFS server,
etc.  

Rik> After all, the VM that Linux currently has was developed mostly
Rik> on machines with less than 1GB of RAM and later encrusted in
Rik> bandaids to make sure the large systems did not fail too badly.

Sure, I understand.  

Rik> As for small system performance, I believe that my patch series
Rik> should cause no performance regressions on those systems and has
Rik> a framework that allows us to improve performance on those
Rik> systems too.

Great!  It would be nice to just be able to track this nicely.

Rik> If you manage to break performance with my patch set somehow,
Rik> please let me know so I can fix it.  Something like the VM is
Rik> very subtle and any change is pretty much guaranteed to break
Rik> something, so I am very interested in feedback.

What are you using to test/benchmark your changes as you develop this
patchset?  What would you suggest as a test load to help check
performance?

John