Messages in this thread | | | Date | Tue, 24 Nov 2009 15:14:21 +0530 | From | "K.Prasad" <> | Subject | Re: [GIT PULL v6] hw-breakpoints: Rewrite on top of perf events v6 |
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On Sun, Nov 08, 2009 at 04:28:54PM +0100, Frederic Weisbecker wrote: > Ingo, > > Please pull the tracing/hw-breakpoints branch that can be found at: > > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git > tracing/hw-breakpoints >
Hi Frederic, Ingo, Here are a few concerns (roughly in decreasing order of priority) about the perf-events integrated hw-breakpoint feature.
- Freeze the breakpoint interfaces: Owing to the many current/potential users of hw-breakpoint feature it is important to provide a stable interface to the end-user. Changes underneath the interface can be done in due course in a manner that does not affect the end-user's behaviour or function signature. The present breakpoint interface requires parameters that are best embedded in a structure for extensibility.
- Proposed migration of register allocation logic to arch-specific files from kernel/hw_breakpoint.c. This is best done early to help easy porting of code to other architectures (we have an active interest in bringing support for PPC64 and S390). If done later, it will entail additional effort in porting for each architecture.
- Fix ptrace bugs that potentially alter the semantics of ptrace.
- Bring either true system_wide support or atleast workaround the side-effects of iterative per-cpu registration using single atomic enablement of all per-cpu breakpoints. This can avoid stray exceptions which would get delivered to the end-user even for failed breakpoint requests.
Thanks, K.Prasad
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