[Dovecot] load increase after upgrade to 2.0.8

Timo Sirainen tss at iki.fi
Fri Dec 10 03:10:01 EET 2010

On 10.12.2010, at 0.54, Stan Hoeppner wrote:

> However, this still doesn't seem to explain Ralf's issue, where the
> kernel stays the same, but the Dovecot version changes, with 2.0.x
> causing the high load and 1.2.x being normal.  Maybe 2.0.x simply causes
> this bug to manifest itself more loudly?

Cor's debugging has so far shown that a single epoll_wait() call can sometimes generate a few thousand voluntary context switches. I can't really understand how that's possible. Those epoll_wait() calls about half of the total voluntary context switches generated by imap processes. We'll see tomorrow if poll() works better or if a small patch I made makes it better.

> This Linux kernel bug doesn't explain the high load reported with 2.0.x
> on FreeBSD either.

Who has reported high load on FreeBSD? So far I know of only Ralf and Cor and both are using Linux.

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