30/07/2021 16:35, Morten Brørup: > > From: Olivier Matz [mailto:olivier.m...@6wind.com] > > Sent: Friday, 30 July 2021 14.37 > > > > Hi Thomas, > > > > On Sat, Jul 24, 2021 at 10:47:34AM +0200, Thomas Monjalon wrote: > > > What's the follow-up for this patch? > > > > Unfortunatly, I still don't have the time to work on this topic yet. > > > > In my initial tests, in our lab, I didn't notice any performance > > regression, but Ali has seen an impact (0.5M PPS, but I don't know how > > much in percent). > > > > > > > 19/01/2021 15:04, Slava Ovsiienko: > > > > Hi, All > > > > > > > > Could we postpose this patch at least to rc2? We would like to > > conduct more investigations? > > > > > > > > With best regards, Slava > > > > > > > > From: Olivier Matz <olivier.m...@6wind.com> > > > > > On Mon, Jan 18, 2021 at 05:52:32PM +0000, Ali Alnubani wrote: > > > > > > Hi, > > > > > > (Sorry had to resend this to some recipients due to mail server > > problems). > > > > > > > > > > > > Just confirming that I can still reproduce the regression with > > single core and > > > > > 64B frames on other servers. > > > > > > > > > > Many thanks for the feedback. Can you please detail what is the > > amount of > > > > > performance loss in percent, and confirm the test case? (I > > suppose it is > > > > > testpmd io forward). > > > > > > > > > > Unfortunatly, I won't be able to spend a lot of time on this soon > > (sorry for > > > > > that). So I see at least these 2 options: > > > > > > > > > > - postpone the patch again, until I can find more time to analyze > > > > > and optimize > > > > > - apply the patch if the performance loss is acceptable compared > > to > > > > > the added value of fixing a bug > > > > > > > > [...] > > > > Statu quo... > > > > Olivier > > > > The decision should be simple: > > Does the DPDK project support segmented packets? > If yes, then apply the patch to fix the bug! > > If anyone seriously cares about the regression it introduces, optimization > patches are welcome later. We shouldn't wait for it.
You're right, but the regression is flagged to a 4-years old patch, that's why I don't consider it as urgent. > If the patch is not applied, the documentation must be updated to mention > that we are releasing DPDK with a known bug: that segmented packets are > handled incorrectly in the scenario described in this patch. Yes, would be good to document the known issue, no matter how old it is. > Generally, there could be some performance to gain by not supporting > segmented packets at all, as a compile time option. But that is a different > discussion. > > > -Morten
