Thanks Darrell, comment inline. On Sat, Jul 1, 2017 at 1:02 AM, Darrell Ball <db...@vmware.com> wrote:
> > > > > *From: *Hui Xiang <xiangh...@gmail.com> > *Date: *Thursday, June 29, 2017 at 6:57 PM > *To: *Darrell Ball <db...@vmware.com> > *Cc: *"Bodireddy, Bhanuprakash" <bhanuprakash.bodire...@intel.com>, " > ovs-discuss@openvswitch.org" <ovs-discuss@openvswitch.org> > *Subject: *Re: [ovs-discuss] max mega flow 64k per pmd or per dpcls? > > > > I am interested about how to define 'reasonable' here, how it is got and > what what is the 'many case'? is there any document/link to refer this > information, please shed me some light. > > > > It is based on real usage scenarios for the number of megaflows needed. > > The usage may be less in most cases. > > In cases where larger, it may imply that more threads are better and > dividing among queues. > Yes, more threads are better, but the overall cores are limited, more threads pinned on cores for OVS-DPDK, less available for vms. > > > Why do think having more than 64k per PMD would be optimal ? > I originally thought that the bottleneck in classifier because it is saturated full so that look up has to be going to flow table, so I think why not just increase the dpcls flows per PMD, but seems I am wrong based on your explanation. > What is your use case(s) ? > My usecase might be setup a VBRAS VNF with OVS-DPDK as an NFV normal case, and it requires a good performance, however, OVS-DPDK seems still not reach its needs compared with hardware offloading, we are evaluating VPP as well, basically I am looking to find out what's the bottleneck so far in OVS-DPDK (seems in flow look up), and if there are some solutions being discussed or working in progress. > Are you wanting for this number to be larger by default ? > I am not sure, I need to understand whether it is good or bad to set it larger. > Are you wanting for this number to be configurable ? > Probably good. > > BTW, after reading part of DPDK document, it strengthens to decrease to copy between cache and memory and get cache hit as much as possible to get fewer cpu cycles to fetch data, but now I am totally lost on how does OVS-DPDK emc and classifier map to the LLC. > > > On Thu, Jun 29, 2017 at 10:47 PM, Darrell Ball <db...@vmware.com> wrote: > > Q: “how it is calculated in such an exact number? “ > > A: It is a reasonable number to accommodate many cases. > > Q: “If there are more ports added for polling, for avoid competing can I > increase the 64k size into a > bigger one?” > > A: If a larger number is needed, it may imply that adding another PMD and > dividing the forwarding > work would be best. Maybe even a smaller number of flows may be best > served with more PMDs. > > > > > > > On 6/29/17, 7:23 AM, "ovs-discuss-boun...@openvswitch.org on behalf of > Bodireddy, Bhanuprakash" <ovs-discuss-boun...@openvswitch.org on behalf > of bhanuprakash.bodire...@intel.com> wrote: > > > > > >I guess the answer is now the general LLC is 2.5M per core so that > there is 64k > > >flows per thread. > > > > AFAIK, the no. of flows here may not have to do anything with LLC. > Also there is EMC cache(8k entries) of ~4MB per PMD thread. > > > > > > Yes the performance will be nice with simple test cases (P2P with 1 > PMD thread) as most of this fits in to LLC. But in real scenarios OvS-DPDK > can be memory bound. > > > > BTW, on my DUT the LLC is 35MB and has 28 cores and so the assumption > of 2.5M/core isn't right. > > > > - Bhanuprakash. > > > > > > > >On Fri, Jun 23, 2017 at 11:15 AM, Hui Xiang <xiangh...@gmail.com> > wrote: > > >Thanks Darrell, > > > > > >More questions: > > >Why not allocating 64k for each dpcls? does the 64k just fit in L3 > cache or > > >anywhere? how it is calculated in such an exact number? If there are > more > > >ports added for polling, for avoid competing can I increase the 64k > size into a > > >bigger one? Thanks. > > > > > >Hui. > > > > > > > > > _______________________________________________ > discuss mailing list > disc...@openvswitch.org > https://urldefense.proofpoint.com/v2/url?u=https-3A__mail. > openvswitch.org_mailman_listinfo_ovs-2Ddiscuss&d=DwIGaQ&c= > uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=- > aL2AdnELLqgfD2paHXevABAGM7lXVTVcc-WMLHqINE&s=pSk0G_pj9n5VvpbG_ > ukDYkjSnSmA9Q9h37XchMZofuU&e= > > >
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