Kernel ticks


Raj Gundi
 

Hi All,

 

I see that the kernel tick is decided by the value given to SYS_CLOCK_TICKS_PER_SEC. For most of the applications, the kernel tick is configured for 1ms or 10ms (corresponding to a value of 1000 or 100 for SYS_CLOCK_TICKS_PER_SEC). I am wondering if it is possible to go below 1ms. I mean, if we have got a very powerful processor, there may be requirements to have something like a 100us tick (considering all trade-offs). Does Zephyr kernel support such requirements?

 

Appreciate any inputs. Thanks in advance.

 

Regards,

Raj


pawel.dunaj@...
 

Hi,
Yes. Even the defaults suggest that as you get default 10000 if TICKLESS_KERNEL.
But for cooperative threads it does not really matter as these are not preempted with timeslice. The only visible benefit is shorter sleep time.
Regard,


Greg Shue
 

Related question:

 

For long-lived battery powered devices a sys tick rate of 100HZ may burn _way_ too much energy.  How slow a sys-tick is supported (1 Hz, 0.5 Hz?) before having to go tickles?

 

Regards,

Greg

 

From: devel@... <devel@...> On Behalf Of Raj Gundi via lists.zephyrproject.org
Sent: Monday, July 12, 2021 8:41 AM
To: devel@...
Subject: [Zephyr-devel] Kernel ticks

 

Hi All,

 

I see that the kernel tick is decided by the value given to SYS_CLOCK_TICKS_PER_SEC. For most of the applications, the kernel tick is configured for 1ms or 10ms (corresponding to a value of 1000 or 100 for SYS_CLOCK_TICKS_PER_SEC). I am wondering if it is possible to go below 1ms. I mean, if we have got a very powerful processor, there may be requirements to have something like a 100us tick (considering all trade-offs). Does Zephyr kernel support such requirements?

 

Appreciate any inputs. Thanks in advance.

 

Regards,

Raj



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