Re: [patch 10/10] Port of blktrace to the Linux Kernel Markers.

Jens Axboe
2007-05-10T09:20:54Z

On Wed, May 09 2007, Mathieu Desnoyers wrote:
> Here is a proof of concept patch, for demonstration purpose, of moving
> blktrace to the markers.
>
> A few remarks : this patch has the positive effect of removing some code
> from the block io tracing hot paths, minimizing the i-cache impact in a
> system where the io tracing is compiled in but inactive.
>
> It also moves the blk tracing code from a header (and therefore from the
> body of the instrumented functions) to a separate C file.
>
> There, as soon as one device has to be traced, every devices have to
> fall into the tracing function call. This is slower than the previous
> inline function which tested the condition quickly. If it becomes a
> show stopper, it could be fixed by having the possibility to test a
> supplementary condition, dependant of the marker context, at the marker
> site, just after the enable/disable test.

Did you benchmark it?

--
Jens Axboe