performance of jailed processes

[Robert Watson]

On Tue, 30 Mar 2004, Dag-Erling Smørgrav wrote:

> Robert Watson <rwatson at freebsd.org> writes:
> > Somewhat more painful suggestion, but could you generate ktraces against a
> > mysql client doing the query inside and out of jail, then using whatever
> > flag sets relative timestamps on kdump, diff the two and see where the
> > substantial differences begin?
> 
> 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...
> 
> 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. 

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. 

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