On 4 November 2014 22:47, Steven Rostedt <[email protected]> wrote: > On Tue, 4 Nov 2014 22:29:24 +0800 > "pang.xunlei" <[email protected]> wrote: > > >> > Migration is not cheap. It causes cache misses and TLB flushes. This is >> > not something that should be taken lightly. >> Ok, thanks! >> But I think the PUSH operation optimized by the former patch is reasonable, >> since PUSH itselft does involve the Migration. Do I miss something? > > For the first patch you may be right, but I want to think about it some > more. I want to make sure we are not adding any other type of overhead > with the extra calls. Yes, this may cause some overhead/latency in idle especially its exit stage, if that can't be accepted, I think it can also be done just in find_lowest_rq() after cpupri_find(), we can modify cpupri_find() for example to return a pri_to_cpu[] index plus one instead of 1, then if the return index equals CPUPRI_NORMAL+1, then iterate the "lowest_mask" with something like cpu_idle() judgement to select the idle cpu.
> > -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
