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Date:      Tue, 30 Mar 2004 16:00:03 -0500 (EST)
From:      Robert Watson <rwatson@freebsd.org>
To:        Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?= <des@des.no>
Cc:        current@freebsd.org
Subject:   Re: performance of jailed processes
Message-ID:  <Pine.NEB.3.96L.1040330155837.93169O-100000@fledge.watson.org>
In-Reply-To: <xzpbrmerrbi.fsf@dwp.des.no>

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On Tue, 30 Mar 2004, Dag-Erling Sm=F8rgrav wrote:

> Robert Watson <rwatson@freebsd.org> writes:
> > Somewhat more painful suggestion, but could you generate ktraces agains=
t a
> > mysql client doing the query inside and out of jail, then using whateve=
r
> > flag sets relative timestamps on kdump, diff the two and see where the
> > substantial differences begin?
>=20
> I'll give it a shot tomorrow.

I've had quite a bit of luck resolving mysql problems in jail using this
approach, fwiw, during some confusion relating to UNIX domain sockets at
an ISP I provide some help to.

> > 13 seconds is too long for most of the potential things I have in mind.=
=2E.
>=20
> although the query only returns one row, it's a pretty big row, so 13
> seconds could be explained by per-syscall or per-packet overhead.=20

Theory goes that there should be no per-read/write system call change in
behavior for TCP with jail.  Jail impacts bind/connect, and potentially
each I/O on UDP for an unbound socket using sendto.=20

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Senior Research Scientist, McAfee Research




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