On Wed, Jul 25, 2012 at 11:15 AM, Nadav Har'El <[email protected]>wrote:
> On Wed, Jul 25, 2012, Oleg Goldshmidt wrote about "Re: High-resolution > user/system times?": > > > Hi, as you know the time(1) command, and the times(2) system call is > > > able to separate a process's running time into "user" and "system" > time, > > > measuring the CPU time in user space and kernel space respectively. > > > > > > However, these only have a jiffy (often 1/250 seconds) resultion. > >... > > > > man 2 getrusage ? > > Thanks. > > The manual page seems promising, talking about microseconds, but I don't > believe it actually has a microsecond resolution. I think it has the > same jiffy resolution that times() has. Do you believe that it does > have microsecond resolution? > No, I know it doesn't. Actually, I looked the kernel code up, I do think that HZ is 100 (by default), and jiffies_to_usecs is faking it. Maybe you need to resort to clock_gettime with CLOCK_REALTIME. Some mentioned related instrumentation earlier in this thread. > I think we're starting to build here a long list of manual-page bugs... > > -- > Nadav Har'El | Wednesday, Jul 25 2012, 6 Av > 5772 > [email protected] > |----------------------------------------- > Phone +972-523-790466, ICQ 13349191 |Evening news begins with 'Good > evening', > http://nadav.harel.org.il |and then proceeds to say why it > isn't. > -- Oleg Goldshmidt | [email protected]
_______________________________________________ Linux-il mailing list [email protected] http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
