Hello, On Wed, Jul 27, 2016 at 05:11:54PM +0300, Grygorii Strashko wrote: > On 07/27/2016 10:03 AM, Uwe Kleine-König wrote: > > On Tue, Jul 26, 2016 at 05:36:49PM +0300, Grygorii Strashko wrote: > >> On 07/26/2016 03:02 PM, Uwe Kleine-König wrote: > >>> Hello, > >>> > >>> these patches are based on next-20160726. I didn't check yet how latency > >>> improves by using these patches, but even if the improvment is small, > >>> it's still a good idea to have them. > >> > >> Sry, but how this will affect on -RT? This is not a raw locks, so > >> they will be converted to rt-mutexes which are sleepable. > >> Or I've missed smth? > > > > They are still locks after all. On -rt I saw for the relevant > > application: > > > > send package | > > take lock | > > write pckt to hw | > > | rcv irq > > | take lock > > | schedule > > drop lock | > > schedule | > > | get pckt from hw > > | drop lock > > > > So reducing the time a lock is taken reduces the chances that the lock > > is contended for another thread which results in extra context switches. > > > Thanks a lot for explanation. So, this is not exactly rt-latency reduction, > but it might improve net performance on -RT. correct?
Well, it's not really rt related, but if you hit a locked lock on rt it hurts more than on !rt. And this results in increased latency. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
