1ms VS 10ms tick

QNX Newsgroups (Archives) qdn.public.articles
1

Hi,

I would like to understand the rationale for QNX setting the tick rate to
1ms for >40Mhz CPUs and to 10ms for slower CPUs.

Thanks,
tim

2

“Tim Whalen” <trwhalen@sympatico.ca> wrote in message
news:99sgvu$4u8$1@inn.qnx.com…

Hi,

I would like to understand the rationale for QNX setting the tick rate to
1ms for >40Mhz CPUs and to 10ms for slower CPUs.

CPU overhead :wink:

For each tick some code in the kernel is executed, the faster
the tick rate the more code is being run. On slow CPU this
can take away an important percentage of available CPU.

Why set the threshold at 40Mzh (i haven’t check that number myself),
probably because if it was 100Mzh some body would have asked
the same question anyway.

Thanks,
tim