On Wed, 08 Apr 2015 12:28:34 -0400 Daniel Wagner <daniel.wagner@xxxxxxxxxxxx> wrote: > A simple hardware latency detector. Use this module to detect large > latencies introduced by the behavior of the underlying system firmware > external to Linux. The hardware latency detector works by disabling > interrupts while running a tight loop taking timestams and measure for > unexplainable gaps in the CPU timestamp counter(s). Any gap indicates > a time when the polling was interrupted and interrupts turned off the > only thing that could do that would be an SMI. > > By default, the module is not enabled until the "enable" file within > the "hwlat_detector" debugfs directory is toggled. > > Jon Masters developed this wonderful SMI detector. For details please > consult Documentation/hwlat_detector.txt. > > [dw: rewrote everything except the detector itself (sample_get()] > > Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx> > Cc: Jon Masters <jcm@xxxxxxxxxx> > Cc: Carsten Emde <C.Emde@xxxxxxxxx> > Cc: Steven Rostedt <srostedt@xxxxxxxxxx> > Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Cc: Mike Galbraith <bitbucket@xxxxxxxxx> > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc; linux-rt-users@xxxxxxxxxxxxxxx > > Link: http://www.spinics.net/lists/linux-rt-users/msg10350.html > --- > Hi, > > Here is my attempt to rewritte hwlat_detector. Most of the code is a > new except the detection routine itself. With some luck I didn't break > it. I hope I updated the documentation correctly and also added all > the credits. > > @Carsten, I haven't found your original post of the hwlatdetect.patch > patch. I assume you have written most of the documentation. I guess > should be also added as copyright holder. > Funny you are working on this. I'm actually working on porting the hwlat_detector to ftrace as a tracer and removing it as a module. It will be similar to the irqsoff tracer, although it wont be doing "latency" tests. It will just report the output to the ring buffer as the other tracers do. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
