Re: Detecting PREEMPT_RT

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Carsten

Am 20.01.2013 um 02:43 schrieb Carsten Emde:

> Unfortunately, this wiki article is old and unmaintained. You're probably right to be a bit suspicious when checking for the "-rt" suffix of the kernel release (uname -r). But looking for the occurrence of "PREEMPT RT" in the kernel version (uname -v) should work. An application may use the system call uname() and check the version element of the utsname structure.

the utsname.version string match is fine, however:

> In addition you may want to make sure the system has high-resolution timers. If so, the timers in /proc/timer_list have ".resolution: 1 nsecs". An application may use the function check_timer() from cyclictest for this purpose:
> static int check_timer(void)
> {
>  struct timespec ts;
> 
>  if (clock_getres(CLOCK_MONOTONIC, &ts))
>    return 1;
> 
>  return (ts.tv_sec != 0 || ts.tv_nsec != 1);
> }

Just tried this on a generic kernel (2.6.32-45-generic #102-Ubuntu SMP Wed Jan 2 21:53:06 UTC 2013 i686 GNU/Linux) and I get ts.tv_sec == 0 and ts.tv_nsec == 1, so it looks this cant be used to tell an RT_PREEMPT from a vanilla kernel

- Michael

--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [RT Stable]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]

  Powered by Linux