On Thu, Jan 07, 2016 at 02:32:23PM -0800, H. Peter Anvin wrote: > On 01/07/16 14:29, H. Peter Anvin wrote: > > > > I would be very interested in knowing if replacing the final clflushopt > > with a clflush would resolve your problems (in which case the last mb() > > shouldn't be necessary either.) > > > > Nevermind. CLFLUSH is not ordered with regards to CLFLUSHOPT to the > same cache line. > > Could you add a sync_cpu(); call to the end (can replace the final mb()) > and see if that helps your case? s/sync_cpu()/sync_core()/ No. I still see failures on Baytrail and Braswell (Pineview is not affected) with the final mb() replaced with sync_core(). I can reproduce failures on Pineview by tweaking the clflush_cache_range() parameters, so I am fairly confident that it is validating the current code. iirc sync_core() is cpuid, a heavy serialising instruction, an alternative to mfence. Is there anything that else I can infer about the nature of my bug from this result? -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
