On Wed, 2007-01-17 at 05:03 -0500, Sander Huijsen wrote: > We wish to increase the HZ value in the Linux kernel from 100 (10ms > period) to 1000 (1 ms period).
It would be useful for you to explain _why_ you want to change the timer period. There are almost certainly much better ways to achieve what you want than globally changing the timer period. You will take a significant performance hit in context switch overhead when reducing the timer period. You should strongly consider using the high-res timers instead. > I’ve changed the actual value of HZ in include/asm-arm/param.h, but I > don’t see any change: timer ticks are still 10ms. This can be shown by > running procinfo –n1 on the DVEVM and examining IRQ35, which is the > System Tick. Its value is increased with exactly 100 every second… > > As far as I can tell, the IRQ35 period is calculated in > arch/arm/mach-davinci/time.c as: ((CLOCK_TICK_RATE / HZ) – 1), where > CLOCK_TICK_RATE equals 27MHz (hardware timer). That's correct. > Who can tell us what we need to do to increase the HZ as used in the > kernel? This patch did it for me, although as I stated above, this is not recommended. Index: linux-2.6.10/include/asm-arm/arch-davinci/param.h =================================================================== --- linux-2.6.10.orig/include/asm-arm/arch-davinci/param.h +++ linux-2.6.10/include/asm-arm/arch-davinci/param.h @@ -27,3 +27,6 @@ * 675 Mass Ave, Cambridge, MA 02139, USA. * */ + +#define HZ 1000 + _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
