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Re: Tuning the clock Tick Time

I think it was my mistake because I did not properly phrase my question.
In RTLinux not only latencies but also periodicity of threads can also be given in terms of Micro-Seconds.

So in eCos when I correspondigly write alarms, I want to be able to set alarms of micro-seconds range.

Is it possible ??

If Context switches are indeed in micro-seconds range, and default tick-time is 100 per second, then how can I find out the exact time for context switch in eCos ?

On Mon, 19 Dec 2005, Gary Thomas wrote:

On Tue, 2005-12-20 at 01:12 +0530, R Vamshi Krishna wrote:

I am using a Pentium IV as my target system and since the system is fast
enough, I want to see to how small can I make the "tick" time be and still
manage my applications.

To that end can anyone tell how can I decrease the tick time (say in
micro-seconds range).

Actually we have an application that runs on RTLinux. I want to see if we
can do that in eCos. RTlinux provides very small latencies (micro-seconds
range). Hence I want to check if eCos can also do that.

eCos can definitely provide micro-second event latencies. This is not related to how fast the clock runs though - a well designed system does not rely on a clock/timer to make things happen.

RTLinux also has a small test that prints all the latencies. Is something like that available for eCos.

Look at CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY and CYGVAR_KERNEL_COUNTERS_CLOCK_DSR_LATENCY in the kernel package. These can be enabled and the 'tm_basic' program will use them, providing a simple measure of clock/timer ISR and DSR latencies.

-- Regards, Vamshi

R.Vamshi Krishna,
M.Tech. CSE (II year),
IIT Bombay
Room no. 320, A-wing, Hostel-12
Mobile : +919869781633

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