Subject: Re: Interactive responsiveness under heavy I/O load
To: None <>
From: Steven M. Bellovin <>
List: tech-kern
Date: 01/26/2004 12:28:57
In message <>, Thor Lancelot Simon writes:
>On Mon, Jan 26, 2004 at 04:30:08PM +0000, John Goerzen wrote:
>> Hello,
>> I have been noticing some disturbing patterns on two different machines
>> I'm trying NetBSD on.  When I am untarring a file, or generally doing
>> anything that is causing large amounts of data to be written at once,
>> interactive performance is seriously degraded.  For instance, while I
>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:

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

since I've been told that those are important.  (This is a kernel from 
22 Jan.)

		--Steve Bellovin,