From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============8268140163972824218==" MIME-Version: 1.0 From: Igor Zhbanov Subject: [Powertop] Some more NaNs in report when CONFIG_TRACING is not enabled Date: Fri, 17 Aug 2012 15:51:36 +0400 Message-ID: <502E3048.6020401@samsung.com> To: powertop@lists.01.org List-ID: --===============8268140163972824218== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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 co= rrectly handle the situation when /sys/kernel/debug is present but /sys/kernel/debu= g/tracing is not. So the PowerTOP will be unable to get information about trace events. And i= nstead of arguing about that or skipping some tests, it will run and produce wrong re= ports. 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_w= akeups(), 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 dis= abled (although the PowerTOP can still report information about devices), but I suppose tha= t the PowerTOP should check whether /sys/kernel/debug/tracing presents and say something i= f not. And as I see the PowerTOP almost never check the result of file opening fun= ctions. If it cannot open a file, the PowerTOP just silently skip it. Thank you. -- = Best regards, Igor Zhbanov, Expert Software Engineer, phone: +7 (495) 797 25 00 ext 3806 e-mail: i.zhbanov(a)samsung.com ASWG, Moscow R&D center, Samsung Electronics 12 Dvintsev street, building 1 127018, Moscow, Russian Federation --===============8268140163972824218==--