Re: Interactive responsiveness under heavy I/O load

On Mon, Jan 26, 2004 at 11:32:52AM -0800, David S. wrote:
> > >
> > >The new I/O sorting algorithm in -current should make this significantly
> > >better.  I am hoping that it can become the default for 2.0.
> > 
> > Thor, I find -current to be almost unusable for interactive work when 
> > there's something I/O-intensive running at the same time.  I have
> > NEW_BUFQ_STRATEGY enabled, as best I can tell.  Here are my vm. sysctl 
> > values, on a 256M machine:
> 
> I can confirm this.  I'm using i386 1.6ZH with NEW_BUFQ_STRATEGY and
> soft updates on IDE disks.  My vm sysctl values are the same as below.
> Yesterday, I upgraded Mozilla and MozillaFirebird on the machine.
> While the source files of those packages was un-tarring, the system
> was dead in the water, and not only for interactive use.  That machine
> also servers NFS from some other disks, and access to those from
> network clients also halted during all of the heavy I/O activity.

I can also toss in a "me too" on this one. NEW_BUFQ_STRATEGY is *not*
stable. I can perform tasks like David describes above without it, and the
system will lag a bit, of course, but it won't become totally unresponsive.
with NEW_BUFQ_STRATEGY, the system becomes totally unusable for upwards of
thirty seconds. (as I stated in a previous mail, after there was a thread
started by Chuck Silvers unless I miss my guess about whether
NEW_BUFQ_STRATEGY should be made the default, my opinion is PLEASE DON'T :)

> > 
> > vm.nkmempages = 16354
> > vm.anonmin = 30
> > vm.execmin = 30
> > vm.filemin = 10
> > vm.maxslp = 20
> > vm.uspace = 16384
> > vm.anonmax = 80
> > vm.execmax = 60
> > vm.filemax = 50
> > vm.bufcache = 20
> > vm.bufmem_lowater = 3348480
> > vm.bufmem_hiwater = 53575680
> > 
> > 

vm.nkmempages = 24551
vm.anonmin = 30
vm.execmin = 20
vm.filemin = 20
vm.maxslp = 20
vm.uspace = 16384
vm.anonmax = 80
vm.execmax = 60
vm.filemax = 60
vm.bufcache = 5
vm.bufmem_lowater = 1256960
vm.bufmem_hiwater = 20111360

-Sean

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