- Mark Moseley moseleymark@gmail.com:
We're on 2.6.32 and the load only goes up when I change dovecot (not when I change the kernel, which I didn't do so far)
If you at some point upgrade to >2.6.35, I'd be interested to hear if the load skyrockets on you.
You mean even more? I'm still hoping it would decrease at some point :) I updated to 2.6.32-27-generic-pae today. I wonder what happens.
I also get the impression that the load average calculation in these recent kernels is 'touchier' than in pre-2.6.35. Even with similar CPU and I/O utilization, the load average on a >2.6.35 both is much higher than pre- and it also seems to react more quickly; more jitter I guess. That's based on nothing scientific though.
Interesting.
Upping the client_limit actually results in less processes, since a single process can service up to #client_limit connections. When I bumped up the client_limit for imap, my context switches plummeted.
Which setting are you using now?
Though as Timo pointed out on another thread the other day when I was asking about this, when that proc blocks on I/O, it's blocking all the connections that the process is servicing.Timo, correct me if I'm wildly off here -- I didn't even know this existed before a week or two ago. So you can then end up creating a bottleneck, thus why I've been playing with finding a sweet spot for imap.
Blocking on /proc? Never heard that before.
I figure that enough of a process's imap connections must be sitting in IDLE at any given moment, so setting client_limit to like 4 or 5 isn't too bad. Though it's not impossible that by putting multiple connections on a single process, I'm actually throttiling the system, resulting in fewer context switches (though I'd imagine bottlenecked procs would be blocked on I/O and do a lot of volcs's).
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