Messages in this thread | | | Subject | Re: [PATCH] irqchip: gicv3-its: Use NUMA aware memory allocation for ITS tables | From | Marc Zyngier <> | Date | Mon, 3 Jul 2017 15:53:49 +0100 |
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Hi Shanker,
On 03/07/17 15:24, Shanker Donthineni wrote: > Hi Marc, > > On 06/30/2017 03:51 AM, Marc Zyngier wrote: >> On 30/06/17 04:01, Ganapatrao Kulkarni wrote: >>> On Fri, Jun 30, 2017 at 8:04 AM, Ganapatrao Kulkarni >>> <gpkulkarni@gmail.com> wrote: >>>> Hi Shanker, >>>> >>>> On Sun, Jun 25, 2017 at 9:16 PM, Shanker Donthineni >>>> <shankerd@codeaurora.org> wrote: >>>>> The NUMA node information is visible to ITS driver but not being used >>>>> other than handling errata. This patch allocates the memory for ITS >>>>> tables from the corresponding NUMA node using the appropriate NUMA >>>>> aware functions. >>> >>> IMHO, the description would have been more constructive? >>> >>> "All ITS tables are mapped by default to NODE 0 memory. >>> Adding changes to allocate memory from respective NUMA NODES of ITS devices. >>> This will optimize tables access and avoids unnecessary inter-node traffic." >> >> But more importantly, I'd like to see figures showing the actual benefit >> of this per-node allocation. Given that both of you guys have access to >> such platforms, please show me the numbers! >> > > I'll share the actual results which shows the improvement whenever > available on our next chips. Current version of Qualcomm qdf2400 doesn't > support multi socket configuration to capture results and share with you. > > Do you see any other issues with this patch apart from the performance > improvements. I strongly believe this brings the noticeable improvement > in numbers on systems where it has multi node memory/CPU configuration.
I agree that it *could* show an improvement, but it very much depends on how often the ITS misses in its caches. For this kind of patches, I want to see two things:
1) It brings a measurable benefit on NUMA platforms 2) it doesn't adversely impact non-NUMA systems
I can deal with (2), but I have no way of evaluating (1), mostly for the lack of an infrastructure exercising multiple ITSs at the same time.
Thanks,
M. -- Jazz is not dead. It just smells funny...
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