Date: Tue, 30 Mar 2004 10:30:54 -0800 From: Julian Elischer <julian@elischer.org> To: =?UTF-8?B?RGFnLUVybGluZyDnv70=?= <des@des.no> Cc: current@freebsd.org Subject: Re: performance of jailed processes Message-ID: <4069BCDE.8040405@elischer.org> In-Reply-To: <xzpisgm46h7.fsf@dwp.des.no> References: <xzpisgm46h7.fsf@dwp.des.no>
next in thread | previous in thread | raw e-mail | index | archive | help
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
--
+------------------------------------+ ______ _ __
| __--_|\ Julian Elischer | \ U \/ / hard at work in
| / \ julian@elischer.org +------>x USA \ a very strange
| ( OZ ) \___ ___ | country !
+- X_.---._/ presently in San Francisco \_/ \\
v
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4069BCDE.8040405>