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Re: Sane support for SMP kernel profiling
I see. I missed changing it in a comment.
On 2010-Dec-11, at 14:13, Thor Simon wrote:
> We've fixed SMP kernel profiling, which worked poorly at best (particularly
> on systems with high HZ) since a lock was taken and released around every
> single entry to mcount. Thanks to Andy for the suggestion as to how.
> The following patch includes:
> * A convenience change to build.sh to make it simpler to
> cross-build profiling kernels (-p)
> * Per-CPU profiling space
> * Changes to kgmon to fetch profiling data per-CPU rather than
> globally on MP systems. gprof already knows how to merge
> multiple profiles so there seems little reason to include this
> functionaity in the kernel code or kgmon, both of which should
> be as small and simple as possible.
> * The MCOUNT macro is cleaned up to an inline function on
> architectures which define PROFILE_TASTEFUL_FUNCTIONS. The idea is
> to eventually eliminate the macro.
> * The kernel and userspace mcount implementations are separated
> into two source files to clean up (some of) a really ugly #ifdef
> * A correct, non-locking mcount implementation is included for
> i386. Other ports still build and should be no worse than they
> were before, but also no better.
> Patch is against netbsd-5. Comments much appreciated.
> Thor Lancelot Simon
> Coyote Point Systems, Inc. <tls%coyotepoint.com@localhost>
> Millerton, NY, USA
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