Am 28.05.2012 10:24, schrieb Ming Lei: > On Mon, May 28, 2012 at 2:56 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx> wrote: >> On Fri, May 25, 2012 at 20:49:07, Thomas Klute wrote: >>> Hi everyone, >>> >>> we're having some trouble getting useful results from Ftrace on OMAP3 >>> (Gumstix Overo). As you can see in the example output below, function >>> duration can't be displayed with a precision higher than about 30.5 us, >>> which matches the frequency of the 32 kHz platform timer. For OMAP1, >>> using OMAP_MPU_TIMER instead of CONFIG_OMAP_32K_TIMER should provide >>> better results [1], but I couldn't find anything similar for OMAP3. Just >>> setting CONFIG_OMAP_32K_TIMER=N didn't change the results. Did I miss >>> anything, or isn't there any more precise timer? >>> >> >> I believe you are using mainline kernel here, if yes, you should be enabling >> the dmtimer using commandline argument, "clocksource="gp_timer". > > Also you need to pass 'nohlt' to kernel since gp_timer can't be kept > when cpu is idled in deep state. I use the linux-omap tree, but adding "clocksource=gp_timer nohlt" to the kernel command line did the trick anyways. :-) Thanks to both of you! Thomas -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
