Re: performance of jailed processes
From: Julian Elischer (julian_at_elischer.org)
Date: 03/30/04
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Date: Tue, 30 Mar 2004 10:30:54 -0800 To: Dag-Erling 翽 <des@des.no>
Dag-Erling Smørgrav wrote:
> Can anyone explain why jailed processes seem to perform much worse
> than non-jailed processes in recent -CURRENT?
>
> Specifically, running a query against a remote MySQL server from
> inside a jail takes an order of magnitude more time than from outside
> the jail. Tcpdump shows that the TCP packets carrying the result are
> evenly spaced, so this is not a matter of the server timing out on a
> DNS lookup or anything like that.
>
> Running a configure script also takes much longer inside the jail than
> outisde, and again, progress is even (though slow), so it is clearly
> not a matter of DNS timing out.
>
> There is no NFS or NIS in the equation either. Parts of the file
> space inside the jail is a nullfs mount, but we've also tried without
> nullfs.
>
> The system currently uses SCHED_ULE, but we had similar trouble with
> SCHED_4BSD on 5.1-RELEASE before we went -CURRENT.
>
> The machine currently has ~2600 processes running in ~400 jails. Is
> it conceivable that be scalability issues, perhaps in the credentials
> code, could cause vastly increased syscall overhead for jailed
that suggests 400 addresses, which suggests that lots of linked lists are being
traversed for received packets..
> processes?
>
> DES
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- Previous message: Lukas Ertl: "if_ndis related panic in propagate_priority"
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