Would this work? https://gerrit.fd.io/r/c/vpp/+/27186
Thanks, Chris. > On May 20, 2020, at 1:44 PM, Christian Hopps <cho...@chopps.org> wrote: > > > >> On May 20, 2020, at 11:39 AM, Damjan Marion via lists.fd.io >> <dmarion=me....@lists.fd.io> wrote: >> >> >> >>> On 20 May 2020, at 16:29, Christian Hopps <cho...@chopps.org> wrote: >>> >>> >>>> On May 20, 2020, at 9:42 AM, Damjan Marion via lists.fd.io >>>> <dmarion=me....@lists.fd.io> wrote: >>>> >>>> >>>> >>>>> On 20 May 2020, at 14:38, Christian Hopps <cho...@chopps.org> wrote: >>>>> >>>>> I'm wondering why I have unix-epoll-input in my worker threads "show >>>>> runtime" results. Couldn't it selectively disable/enable itself based on >>>>> whether it actually had any work to do (things to poll)? I'm aware it >>>>> modifies its behavior when there are other polling nodes running, but it >>>>> still is taking time to run occasionally, and I'm not sure why. >>>> >>>> It. is needed there for handling interrupts, and probably nobody bothered >>>> to spend time on adding some logic to turn it off if there is no work for >>>> him as it’s impact on performance is negligible. >>> >>> Ok, thanks. For me its running about 1550ns per call which, if I did my >>> math right, represents ~92 packets (min 46 octets == 84 ethernet octets) at >>> 40GE and ~23 packets on a 10GE. >> >> so your core does 40Gb linerate with 64 byte packets :) > > No. :) > > I'm tyring to get the best I can from imix on the user side, and 1500 octet > (full MTU) fixed interval sending on the secure tunnel side. I wouldn't > expect the current processors to be able to handle small packets line rate on > 100G interfaces, in any case. > >> My math is: >> >> - Best case we do around 100 clock cycles per packet. >> - If cpu is running at 2.5GHz that means 40ns per packet. >> - in 1550ns we can process ~39 packets. >> - 100 clock cycles per packet means 25Mpps @ 2.5GHz >> >> 39 packets less processed out of 25M means performance impact is 0,000156%. > > 1550ns is a per call stat I believe. It seems to average around ~252 calls > per second for me so thats 9828 packets. If those are 9k packets that's > 707Mbps of bandwidth (9828*9000*8=707616000). Even at 1500 it represents 118 > Mbps (117936000). Looking at the code though it's basically being called > every 1024 (1025?) loops. > > My main issue though is that people are going to be paying attention to > timing with my application (IPTFS), so odd blips in packet arrival will be > noticed, and then have to be explained and justified. > > I'll try disabling it with a hack for now. :) > > Thanks, > Chris. > >> Makes sense? >> >> — >> Damjan >> >> >> >> > >
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