On Thu, Jul 06, 2017 at 11:14:00AM -0700, Ray Jui wrote: > On 7/6/17 8:08 AM, Will Deacon wrote: > > On Wed, Jul 05, 2017 at 04:24:22PM -0700, Ray Jui wrote: > >> However, with the fix patch, I can still see the deadlock message when I > >> have > 32 iperf TX threads active in the system: > > > > Damn. We've been going over this today and the only plausible theory seems > > to be that concurrent TLB syncs are causing the completion to be pushed out, > > resulting in timeouts. > > > > Can you try this patch below, instead of the one I sent before, please? > > > > Thanks, > > > > Will > > > > --->8 > > Good news! I can confirm that with the new patch below, the error log of > "TLB sync timed out" is now gone. I ran 20 iterations of the iperf > client test with 64 threads spread across 8 CPUs. The error message used > to coming out very quickly with just one iteration. But now it's > completely gone.
Good, I'll queue this is as a fix then. Thanks for testing! > At the same time, I do seem to observe a slight impact on performance > when multiple threads are used, but I guess that is expected, given that > a spin lock is added to protect the TLB sync. Hopefully that performance will pick up again once we defer the sync to the end of iommu_unmap. Will _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
