[ltt-dev] tracepoint layer and marker layer

Jiaying Zhang jiayingz at google.com
Fri Sep 19 14:56:06 EDT 2008

On Fri, Sep 19, 2008 at 11:23 AM, KOSAKI Motohiro <
kosaki.motohiro at jp.fujitsu.com> wrote:

> Hi
> > Hi Folks,
> >
> > I have a general question about LTTng kernel code. As I understand, LTTng
> > adds an extra tracepoint layer between the traced subsystems and the
> > marker layer. The extra code added by the tracepoint layer seems to
> > introduce
> > noticeable overhead according to my measurements.
> Could you post your mesurement way and result?

I measured my results on a multi-processor machine with the tbench
benchmark http://samba.org/ftp/tridge/dbench/.
The detailed results were posted at
(I should have referred to the link in my original email, sorry about that).

> My past mesurement indicate tracepoint overhead is ignoreble low.

Could you share your measurements and results? E.g., the kernel version
and LTTng patch version, the benchmark you used, your LTTng kernel
the machine type, and so on. Thanks a lot!


> > I wonder whether it will
> > be more efficient and simpler if we let subsystems call the marker layer
> > directly?
> > Any thought?
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