On 07/12/2016 03:09 AM, Marc Zyngier wrote:
Hi Shanker,I have seen at least 5% performance gain when I was testing direct VLPI feature
On 12/07/16 04:36, Shanker Donthineni wrote:
Read-allocation hints are not enabled for both the GIC-ITS and GICRWhile I'm not opposed to such a change, I'd like to see some evidence
tables. This forces the hardware to always read the table contents
from an external memory (DDR) which is slow compared to cache memory.
Most of the tables are often read by hardware. So, it's better to
enable Read-allocate hints in addition to Write-allocate hints in
order to improve the GICR_PEND, GICR_PROP, Collection, Device, and
vCPU tables lookup time.
that this actually makes a difference. Have you measured an improvement
on a particular implementation? If so, could you share your benchmarking
method so that it could be be measured on others as well?
on Qualcomm emulation platforms. On Silicon, this gain is not noticeable.