Date: Fri, 10 Feb 2006 14:57:26 -0500 From: Marcos Bedinelli <bedinelli@madhaus.cns.utoronto.ca> Cc: freebsd-net@freebsd.org Subject: Re: Network performance in a dual CPU system Message-ID: <63274172a54fb70a88d6cb55b9ae6e23@madhaus.cns.utoronto.ca> In-Reply-To: <711b7ec873f31bc5be50ce477313fac3@madhaus.cns.utoronto.ca> References: <7bb8f24157080b6aaacb897a99259df9@madhaus.cns.utoronto.ca> <43ECB1E7.8010308@mac.com> <711b7ec873f31bc5be50ce477313fac3@madhaus.cns.utoronto.ca>
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Hi,
On 10-Feb-06, at 13:06, Chuck Swiger wrote:
> Marcos Bedinelli wrote:
> [ ... ]
>> mull [~]$vmstat -i
>> interrupt total rate
>> irq1: atkbd0 3466 0
>> irq6: fdc0 10 0
>> irq13: npx0 1 0
>> irq14: ata0 47 0
>> irq21: fxp1 20462527 8
>> irq28: bge0 3511765157 1444
>> irq29: bge1 3633124373 1494
>> irq30: aac0 1842472 0
>> cpu0: timer 566751007 233
>> Total 7733949060 3181
>
> Interesting, what do you have HZ ("sysctl kern.clockrate") set to?
> Does setting
> it to somewhere around 500, 1000, or 2000 help? You're definitely
> going to want
> to increase HZ if you enable polling mode...
mull [~]$sysctl kern.clockrate
kern.clockrate: { hz = 1000, tick = 1000, profhz = 666, stathz = 133 }
>> mull [~]$netstat -m
>> 644/646/1290 mbufs in use (current/cache/total)
>> 643/407/1050/17088 mbuf clusters in use (current/cache/total/max)
>> 0/5/4528 sfbufs in use (current/peak/max)
>> 1447K/975K/2422K bytes allocated to network (current/cache/total)
>> 0 requests for sfbufs denied
>> 0 requests for sfbufs delayed
>> 0 requests for I/O initiated by sendfile
>> 0 calls to protocol drain routines
>
> You might try increasing the # of kern.ipc.nmbclusters, say by a
> factor of 2.
> This may not help much, seems like you're bottlenecking servicing the
> bge
> interrupts.
>
> I assume you've read "man tuning" and do not have something like
> WITNESS enabled
> in your kernel? :-)
WITNESS is not part of my current KERNCONF file.
To be honest, I didn't read the whole "man tuning" document because
there are many parts that don't apply to this situation. However, the
"CPU, MEMORY, DISK, NETWORK" section is quite clear about the
following:
"If your system runs out of CPU (idle times are perpetually 0%) then
you need to consider upgrading the CPU or moving to an SMP motherboard
(multiple CPU's), or perhaps you need to revisit the programs that are
causing the load and try to optimize them."
That's basically the problem I am experiencing: memory is fine, swap is
fine, disk access is fine, CPU utilization is way high...
The machine is in production and needs to have its performance improved
asap. Consequently, we are fine with the idea of spending some $ with a
second processor, provided that someone can tell me whether such matter
can be solved using this approach. What we would like to avoid is
spending $ with a second CPU that ultimately won't do any good for us.
Cheers!
--
Marcos
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