On Thu, Nov 05, 2015 at 04:11:21PM -0500, David Miller wrote: > > And for the record Sowmini fixed a lot of the lock contention: > > commit ff7d37a502022149655c18035b99a53391be0383 > Author: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx> > Date: Thu Apr 9 15:33:30 2015 -0400 > > Break up monolithic iommu table/lock into finer graularity pools and lock > The poor rds-stress results w/o IOMMU bypass I sent in early post were taken from kernel that has the above patch and that has all the needed changes in arch/sparc to use this new feature. It seems that it worked well for 10G ETH IOMMU lock contention but it still not solving the rds-stress issue. The difference can be from: 1. Lock contention still left with this enhancement <-- zero in bypass 2. Overhead to setup the IOMMU mapping <-- almost zero in bypass (require 1 HV call) 3. Overhead to use the IOMMU mapping <-- not sure how to measure this 4. Overhead to tear the IOMMU mapping <-- zero in bypass -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
