From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Mon, 3 Jul 2017 15:53:49 +0100 Subject: [PATCH] irqchip: gicv3-its: Use NUMA aware memory allocation for ITS tables In-Reply-To: References: <1498405569-463-1-git-send-email-shankerd@codeaurora.org> Message-ID: <27b46938-ae23-9750-e0c7-09fa472d3297@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 >>> wrote: >>>> Hi Shanker, >>>> >>>> On Sun, Jun 25, 2017 at 9:16 PM, Shanker Donthineni >>>> 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...