On Wed, Sep 04, 2013 at 02:32:49PM +0200, Michael Kerrisk (man-pages) wrote: > Hi Rodrigo, > > On Tue, Sep 3, 2013 at 12:05 PM, Rodrigo Campos <rodrigo@xxxxxxxxxxx> wrote: > > As confirmed by peterz on IRC, this note is obsolete: > > > > <peterz> rata: that section is obsolete; CLOCK_THREAD_CPUTIME_ID is good > > <peterz> rata: CLOCK_PROCESS_CPUTIME_ID is also correct > > > > So this patch just removes it. > > Clearly, the page needs amending. However, ideal would be to describe > *when* the section became obsolete (which kernel version). Do you or > Peter know, or have an idea how we can determine that information? I don't know. But looking at the git repo, it seems in the first git commit (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2) it was already safe, because in kernel/posix-cpu-timers.c cpu_clock_sample() uses the scheduler to get the value. And the basic pattern: posix_cpu_clock_get() --> posix_cpu_clock_get() --> cpu_clock_sample() (for the case of CLOCK_THREAD_CPUTIME_ID) seems unchanged. So, if I guess it was safe on those days too. And for CLOCK_PROCESS_CPUTIME_ID, something similar happens if I follow the code correctly. The call chain I see is: process_cpu_clock_get() --> posix_cpu_clock_get() --> cpu_clock_sample_group() --> cpu_clock_sample_group_locked() And if I follow the clock macros correctly, ends up calling cpu_clock_sample_group_locked() with CPUCLOCK_SCHED, which calls the scheduler and I *expect* that to be safe too. But I would **really** like if Peter can confirm this, as I really don't know :-) Btw, if in the first git commit it was safe, should I try to look to the history before it ? Thanks a lot, Rodrigo -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
