From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============8757466950438909204==" MIME-Version: 1.0 From: Chris Ferron Subject: Re: [Powertop] Some more NaNs in report when CONFIG_TRACING is not enabled Date: Fri, 17 Aug 2012 09:34:05 -0700 Message-ID: <502E727D.7040306@linux.intel.com> In-Reply-To: 502E3048.6020401@samsung.com To: powertop@lists.01.org List-ID: --===============8757466950438909204== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On 08/17/2012 04:51 AM, Igor Zhbanov wrote: > Hello! > > When you run the PowerTOP on the kernel with CONFIG_TRACING disabled, > you will get several NaNs (not a number) in the report. PowerTOP = > doesn't correctly > handle the situation when /sys/kernel/debug is present but = > /sys/kernel/debug/tracing is not. > > So the PowerTOP will be unable to get information about trace events. = > And instead of > arguing about that or skipping some tests, it will run and produce = > wrong reports. > > Since there will be no trace events captured, the measurement_time = > variable > in src/process/do_process.c will remain zero. So the functions like = > total_wakeups(), > total_gpu_ops(), total_disk_hits(), etc. will happily divide total by = > zero. > > Yes, I know that it is not very useful to run the PowerTOP with = > tracing disabled (although > the PowerTOP can still report information about devices), but I = > suppose that the PowerTOP > should check whether /sys/kernel/debug/tracing presents and say = > something if not. > > And as I see the PowerTOP almost never check the result of file = > opening functions. > If it cannot open a file, the PowerTOP just silently skip it. > > Thank you. > Great, thanks, I will start look at this. -Chris --===============8757466950438909204==--