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Re: [patch 1/4] Linux Kernel Markers - Architecture Independent Code
- From: "Frank Ch. Eigler" <fche at redhat dot com>
- To: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>
- Cc: Roland McGrath <roland at redhat dot com>, "Frank Ch. Eigler" <fche at redhat dot com>, Denys Vlasenko <vda dot linux at googlemail dot com>, systemtap at sources dot redhat dot com, Christoph Hellwig <hch at infradead dot org>, Rusty Russell <rusty at rustcorp dot com dot au>, akpm at linux-foundation dot org, linux-kernel at vger dot kernel dot org
- Date: Fri, 26 Oct 2007 10:28:10 -0400
- Subject: Re: [patch 1/4] Linux Kernel Markers - Architecture Independent Code
- References: <20070919113737.GA18177@Krystal> <firstname.lastname@example.org> <email@example.com> <20070921125819.GA13129@Krystal> <20070921133006.GF8964@redhat.com> <20070921133820.GD13129@Krystal> <20071015194120.GA22562@redhat.com> <20071015231209.GA18994@Krystal> <20071015235033.321E84D0389@magilla.localdomain> <20071025191722.GA6114@Krystal>
On Thu, Oct 25, 2007 at 03:17:22PM -0400, Mathieu Desnoyers wrote:
> Since gcc is required to build the systemtap probes on the development
> marchine, I don't see why it would be much harder to also require prople
> to install drawf ? Or maybe the "crash" tool ?
The crash tool requires the dwarf data to work. The dwarf data for an
entire kernel (including all the modules) is on the order of hundreds
of megabytes. The symbol & marker list would be one thousandth the
size. You can see the deployment attractiveness of the latter.
> I guess you must already need to extract the symbols for your kprobes.
> Do you use kallsyms for this?
Nope. /proc/kallsyms is a another run-time-only source of data, and
so is not applicable for off-line (ahead-of-time) mapping.
> I would rather prefer not to implement superfluous built-time data
> extraction in the kernel build system just to make userspace
> simpler. [...]
It is not superfluous, as it would solve a real distribution problem.