Messages in this thread | | | Subject | Re: [RFC] systemtap: begin the process of using proper kernel APIs (part1: use kprobe symbol_name/offset instead of address) | From | (Frank Ch. Eigler) | Date | Fri, 18 Jul 2008 09:02:19 -0400 |
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Peter Zijlstra <peterz@infradead.org> writes:
> [...] >> Right now x86 doesn't really have a good reliable unwinder that >> works without frame pointer. I think systemtap >> recently switched to Jan Beulich's dwarf2 unwinder. Before >> switching to the in kernel unwinder that one would need to be >> re-merged again. > > Those are two separate issues. > > 1) stap ought to use the kernel's infrastructure and not re-implement > its own. > 2) if the kernel's infrastructure doesn't meet requirements, improve > it.
They are related to the extent that readers may not realize some implications of systemtap being/becoming a *kernel-resident* but not *kernel-focused* tool.
For example, we're about to do unwinding/stack-traces of userspace programs. To what extent do you think the kernel unwinder (should one reappear in git) would welcome patches that provide zero benefit to the kernel, but only enable a peculiar (nonintrusive) sort of unwinding we would need for complex userspace stacks?
- FChE
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