[lttng-dev] Non-Preempt Test v1.01

[Aaron Fabbri]

Thanks for sharing this, will check it out if I get a chance.  Do you
have a http git url that I can clone?  I'm behind a firewall.

On Mon, Oct 14, 2013 at 12:05 PM, Raphaël Beamonte
<raphael.beamonte at gmail.com> wrote:
> Hi all !
>
> I just released the Non-Preempt Test (npt) version 1.01 which is
> available here: http://git.dorsal.polymtl.ca/?p=npt.git
>
> The purpose of this tool is to simulate a small real-time system that
> runs with a high priority without being stopped or preempted. To do so,
> it first sets its environment (cpu affinity, RT scheduler, memory locked
> into RAM with mlockall) and can optionally disable the local IRQs if
> compiled with the right options (not defined by default).
>
> The core of the application is a loop that calculates the time gap
> between the start of two consecutive loops using the rdtsc asm
> instruction, thus a similarity with the hwlat_detector kernel module for
> kernel analysis. At the end of its execution, npt computes latencies
> statistics for each loop and generates a histogram showing the different
> latencies reached and the number of time it reached each one.
>
> This tool can be used to analyse and identify overhead of different
> realtime applications as we can compare the latencies in each loops and
> thus identify the added latency from a "blank" run. It is released
> LTTng-ready and can thus be easily traced. Next versions could include
> other userspace tracers ability.
>
> Feedback, collaborations and contributions are welcome!
>
> Regards,
> Raphaël Beamonte
>