On 07/31/13 17:13, Timur Tabi wrote: > On 07/31/2013 07:04 PM, Stephen Boyd wrote: >> If it yields why are we using udelay? Why not usleep_range()? It would >> be useful to have a variant that worked in interrupt context and it >> looked like that was almost possible. > I've never heard of usleep_range() before, so I don't know if it > applies. Apparently, udelay() includes its own call to cpu_relax(). Is > it possible that cpu_relax() is a "lightweight" yield, compared to sleeping? cpu_relax() is usually just a compiler barrier or an instruction hint to the cpu that it should cool down because we're spinning in a tight loop. It certainly shouldn't be calling into the scheduler. > > FYI, you might want to look at the code reviews for spin_event_timeout() > on the linuxppc-dev mailing list, back in March 2009. > Sure. Any pointers? Otherwise I'll go digging around the archives. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
