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Experimental Physics and
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Hi Érico, On Fri, Jan 6, 2023 at 11:48 AM Érico Nogueira Rolim via Tech-talk <tech-talk at aps.anl.gov> wrote:
sysconf provides information about the system to the user. Last time I checked (but this was many years ago) the tick rate for Linux is configured at the kernel's build time: if sysconf(_SC_CLK_TCK) is returning 100, that means the kernel has been built with a 100 Hz tick rate, and that's about it. Years ago there was the option of building the kernel with higher rates (for more responsive systems), from top of my head I believe the alternative values were 350Hz (maybe 250? can't remember) and 1000Hz, plus an additional "NO_HZ" mode where you build a "tickless kernel" but this is of no use to us, I believe. Googling a bit I see a "divider" kernel parameter so that a 1000Hz compiled value can be divided a boot time to the one we want to use (eg. divider=10 -> 100Hz), but I'm not sure if this is the case for Barret. At best the kernel might be built with a 1000Hz, with a "divider=10" by default in the boot options, and it would be just a matter of changing that. At worst default kernel is simply built configured to use 100Hz, and then a different pre-compiled one could be used (distros often include one with PREEMPT built in, maybe at 1000Hz), and failing everything else a custom kernel could be built. Cheers, Ricardo
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ANJ, 06 Jan 2023 |
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