On Wed, Jan 12, 2022 at 3:37 AM Marc Zyngier <maz@xxxxxxxxxx> wrote: > > On Tue, 11 Jan 2022 22:16:01 +0000, > Jing Zhang <jingzhangos@xxxxxxxxxx> wrote: > > > > On Tue, Jan 11, 2022 at 2:30 AM Marc Zyngier <maz@xxxxxxxxxx> wrote: > > > > > > On Mon, 10 Jan 2022 21:04:41 +0000, > > > Jing Zhang <jingzhangos@xxxxxxxxxx> wrote: > > > > > > > > For ARM64, if no vgic is setup before the dirty log perf test, the > > > > userspace irqchip would be used, which would affect the dirty log perf > > > > test result. > > > > > > Doesn't it affect *all* performance tests? How much does this change > > > contributes to the performance numbers you give in the cover letter? > > > > > This bottleneck showed up after adding the fast path patch. I didn't > > try other performance tests with this, but I think it is a good idea > > to add a vgic setup for all performance tests. I can post another > > patch later to make it available for all performance tests after > > finishing this one and verifying all other performance tests. > > Below is the test result without adding the vgic setup. It shows > > 20~30% improvement for the different number of vCPUs. > > +-------+------------------------+ > > | #vCPU | dirty memory time (ms) | > > +-------+------------------------+ > > | 1 | 965 | > > +-------+------------------------+ > > | 2 | 1006 | > > +-------+------------------------+ > > | 4 | 1128 | > > +-------+------------------------+ > > | 8 | 2005 | > > +-------+------------------------+ > > | 16 | 3903 | > > +-------+------------------------+ > > | 32 | 7595 | > > +-------+------------------------+ > > | 64 | 15783 | > > +-------+------------------------+ > > So please use these numbers in your cover letter when you repost your > series, as the improvement you'd observe on actual workloads is likely > to be less than what you claim due to this change in the test itself > (in other words, if you are going to benchamark something, don't > change the benchmark halfway). Sure. Will clarify this in the cover letter in future posts. Thanks, Jing > > M. > > -- > Without deviation from the norm, progress is not possible.
