Re: Status of systemtap in Debian
On 16/02/10 at 22:17 +0100, Kurt Roeckx wrote:
> On Tue, Feb 16, 2010 at 09:13:06PM +0100, Lucas Nussbaum wrote:
> > - disk space on buildds: at least 2 GiB are required to build a kernel
> > with debuginfo. (that doesn't sound too hard to satisfy)
> There currently are packages that require more diskspace than
> that, for instance the linux-2.6 package on i386 uses 4.7 GB,
> while it uses 2.6 GB on amd64.
> I guess it requires an additional 450 MB per kernel flavor
> or maybe a multiple of that for temporary files that also
> contain that?
> The biggest package I could find in a short time seem to be:
> qt4-x11: 7818730k (8058048k latest)
> openoffice.org: 7652264k (7629368k latest)
> openjdk-6: 7152062k (7443004k latest)
> linux-2.6: 4707725k (6319992k latest)
> opencascade: 4619392k (4619392k latest)
> wxwidgets2.8: 4215131k (4297664k latest)
> ghc6: 4015377k (4689676k latest)
> slicer: 3680980k (3680980k latest)
> gcc-snapshot: 3663284k (3663284k latest)
> pyside: 3548760k (3548760k latest)
> boost1.38: 3497562k (3630040k latest)
> (This is acros several arches.)
> Do you know if there is any cost in cpu time for this?
At build time, of course, generating the debug info takes more time.
At run time, I don't think that a kernel built with CONFIG_KPROBES and
CONFIG_DEBUGINFO has any overhead, at least on i386/amd64 (remember that
all other distros ship KPROBES-enabled kernels). Since it depends on the
implementation of kprobes, which is architecture-specific, it is
possible that there is an overhead on some architectures.