Abhishek, That frequency variable doesn't need to be the CPU frequency.
If you look at opal/mca/timer/linux/timer_linux_component.c:opal_timer_linux_find_freq() you will see the initialization for opal_timer_linux_freq. In the case of PPC the time stamp counter runs at a frequency, distinct from that of the CPU, known as the timebase. The code checks for that setting in /proc/cpuinfo before looking for the cpu frequency (also in /proc/cpuinfo). Of course, something like sysctl() or ioctl() might be needed on some platforms to find the same information. -Paul On Fri, May 20, 2016 at 2:25 AM, Abhishek Joshi <abhishek.jo...@broadcom.com > wrote: > Hi, > > In amd64, we have rdtsc instruction which uses a timer updated at cpu > frequency. The frequency is given by variable, opal_timer_linux_freq which > is the cpu frequency. > > Consider the case where a timer updated at non-cpu frequency is to be used. > > Question: In this case, how do we specify the frequency of the timer? > > > -- > Abhishek > > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: https://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2016/05/19006.php > -- Paul H. Hargrove phhargr...@lbl.gov Computer Languages & Systems Software (CLaSS) Group Computer Science Department Tel: +1-510-495-2352 Lawrence Berkeley National Laboratory Fax: +1-510-486-6900
