On Fri, Jul 19, 2019 at 09:55:39AM +0530, Ganapatrao Kulkarni wrote: > On Thu, Jul 11, 2019 at 10:58 PM Will Deacon <w...@kernel.org> wrote: > > This is a significant rework of the RFC I previously posted here: > > > > https://lkml.kernel.org/r/20190611134603.4253-1-will.dea...@arm.com > > > > But this time, it looks like it might actually be worthwhile according > > to my perf profiles, where __iommu_unmap() falls a long way down the > > profile for a multi-threaded netperf run. I'm still relying on others to > > confirm this is useful, however. > > > > Some of the changes since last time are: > > > > * Support for constructing and submitting a list of commands in the > > driver > > > > * Numerous changes to the IOMMU and io-pgtable APIs so that we can > > submit commands in batches > > > > * Removal of cmpxchg() from cmdq_shared_lock() fast-path > > > > * Code restructuring and cleanups > > > > This current applies against my iommu/devel branch that Joerg has pulled > > for 5.3. If you want to test it out, I've put everything here: > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=iommu/cmdq > > > > Feedback welcome. I appreciate that we're in the merge window, but I > > wanted to get this on the list for people to look at as an RFC. > > I have tried branch iommu/cmdq on ThunderX2. I do see there is drastic > reduction in CPU bandwidth consumption(from 15 to 20% to 1 to 2% in > perf top) from SMMU CMDQ helper functions, when I run iperf with more > than 64 clients(-P 64). However I have not noticed any measurable > performance improvement in iperf results. IMO, this might/should help > in performance improvement of IO intensive workloads. > > FWIW, you can add, > Tested-by: Ganapatrao Kulkarni <gkulka...@marvell.com>
Brilliant, thanks. Your measurements reflect mine in that I can saturate the NICs I have access to regardless of these changes, but the CPU time is drastically reduced. Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
