On 06/22 10:27:01, Savolainen, Petri (Nokia - FI/Espoo) wrote: > I was asking to make sure that performance impact has been checked also when > timers are not used, e.g. l2fwd performance before and after the change. It > would be also appropriate to test impact in the worst case: l2fwd type > application + a periodic 1sec timeout. Timer is on, but timeouts come very > unfrequently (compared to packets). > > It seems that no performance tests were run, although the change affects > performance of many applications (e.g. OFP has high packet rate with timers). > Configuration options should be set with defaults that are acceptable > trade-off between packet processing performance and timeout accuracy.
If timers are not used, the overhead is just checking a RO variable (post global init). If timers are used, CONFIG_ parameters have been provided. The defaults for these parameters came from the work to drastically reduce jitter of timer processing which is documented here [1] and presented at Linaro Connect here [2]. If you speculate that these defaults might need to be changed, e.g. l2fwd, we welcome collaboration and data. But, this is not a blocking issue for this patch right now. [1] https://docs.google.com/document/d/1sY7rOxqCNu-bMqjBiT5_keAIohrX1ZW-eL0oGLAQ4OM/edit?usp=sharing [2] http://connect.linaro.org/resource/bud17/bud17-320/ > -Petri > > > From: Maxim Uvarov [mailto:maxim.uva...@linaro.org] > Sent: Thursday, June 22, 2017 11:22 AM > To: Honnappa Nagarahalli <honnappa.nagaraha...@linaro.org> > Cc: Savolainen, Petri (Nokia - FI/Espoo) <petri.savolai...@nokia.com>; > lng-odp-forward <lng-odp@lists.linaro.org> > Subject: Re: [lng-odp] [API-NEXT PATCH v4] timer: allow timer processing to > run on worker cores > > Petri, do you want to test performance before patch inclusion? > Maxim. > > On 21 June 2017 at 21:52, Honnappa Nagarahalli > <mailto:honnappa.nagaraha...@linaro.org> wrote: > We have not run any performance application. In our Linaro connect > meeting, we presented numbers on how it improves the timer resolution. > At this point, there is enough configuration options to control the > effect of calling timer in the scheduler. For applications that do not > want to use the timer, there should not be any change. For > applications that use timers non-frequently, the check frequency can > be controlled via the provided configuration options. > > On 20 June 2017 at 02:34, Savolainen, Petri (Nokia - FI/Espoo) > <mailto:petri.savolai...@nokia.com> wrote: > > Do you have some performance numbers? E.g. how much this slows down an > > application which does not use timers (e.g. l2fwd), or an application that > > uses only few, non-frequent timeouts? > > > > Additionally, init.h/feature.h is not yet in api-next - so this would not > > build yet. > > > > > > -Petri > > > > > >> -----Original Message----- > >> From: lng-odp [mailto:mailto:lng-odp-boun...@lists.linaro.org] On Behalf Of > >> Honnappa Nagarahalli > >> Sent: Tuesday, June 20, 2017 7:07 AM > >> To: Bill Fischofer <mailto:bill.fischo...@linaro.org> > >> Cc: lng-odp-forward <mailto:lng-odp@lists.linaro.org> > >> Subject: Re: [lng-odp] [API-NEXT PATCH v4] timer: allow timer processing > >> to run on worker cores > >> > >> Are you saying we should be good to merge this now? > >> > >> On 19 June 2017 at 17:42, Bill Fischofer <mailto:bill.fischo...@linaro.org> > >> wrote: > >> > On Mon, Jun 19, 2017 at 4:19 PM, Honnappa Nagarahalli > >> > <mailto:honnappa.nagaraha...@linaro.org> wrote: > >> >> Hi Bill/Maxim, > >> >> I do not see any further comments, can we merge this to api-next? > >> >> > >> >> Thanks, > >> >> Honnappa > > > > >
