Messages in this thread |  | | From | "H. Peter Anvin" <> | Subject | Re: Wild thangs, was: sendmail fails to deliver mail with attachments in /var/spool/mqueue | Date | 10 Nov 2000 17:18:13 -0800 |
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Followup to: <3A0C929B.EE6F7137@linux.com> By author: David Ford <david@linux.com> In newsgroup: linux.dev.kernel > > - Requires high load average allowance > Incorrect. Same machine barely spiked a tenth of a point for this load and dropped > back to .05. Only time I adjusted the configured load average allowance was back in my > naive days and we got hit with 80,000 in the queue at one time from multiple spammers. > Part of this test's load came from numerous things running and the mail sending required > spinup of the drive which blocked. >
Well, I think it does, but not because it itself is generating much of a load. I had it block traffic on my desktop machine while doing a kernel compile; I run with high parallelism and the load occationally spikes in the high 20's. However, the machine is perfectly responsive, and so I was a little taken back by this.
The way Linux computes the load average really does call for higher limits than what BSD does. This isn't inherently a "good" or "bad" thing -- it's just a fact of life. That being said, it probably would be useful if the Sendmail people would provide higher default limits in cf/ostype/linux.m4 than for other systems.
The one thing about load average that is making it a bit hard to deal with is that workloads on modern machines tend to vary a little too quickly for the standard load average time constants to deal well with them. It's probably fine for throttling down a machine that is getting killed with requests, but not really enough to keep, say, parallel make without a limit ("make -j" as opposed to "make -j5") from forking the machine to the point where the make itself fails before knowing what just hit it.
-hpa
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