+Walter test it Jeff, How much CPU does the EC2 hypervisor use? I have heard 5% but that is for a normal workload, and is mostly consumed during system calls or context changes. So it is quite understandable that frequent time calls would take a bigger bite in the AWS cloud compared to bare metal. Sorry, my words are mostly conjecture so please ignore. Cheers -- Rick
On May 3, 2017 2:35:33 PM EDT, Jeff Wartes <jwar...@whitepages.com> wrote: > >It’s presumably not a small degradation - this guy very recently >suggested it’s 77% slower: >https://blog.packagecloud.io/eng/2017/03/08/system-calls-are-much-slower-on-ec2/ > >The other reason that blog post is interesting to me is that his >benchmark utility showed the work of entering the kernel as high system >time, which is also what I was seeing. > >I really want to go back and try some more tests, including (now) >disabling the timeAllowed param in my query corpus. >I think I’m still a few weeks of higher priority issues away from that >though. > > >On 5/2/17, 1:45 PM, "Tomás Fernández Löbbe" <tomasflo...@gmail.com> >wrote: > >I remember seeing some performance impact (even when not using it) and >it >was attributed to the calls to System.nanoTime. See SOLR-7875 and >SOLR-7876 >(fixed for 5.3 and 5.4). Those two Jiras fix the impact when >timeAllowed is > not used, but I don't know if there were more changes to improve the >performance of the feature itself. The problem was that System.nanoTime >may >be called too many times on indices with many different terms. If this >is >the problem Jeff is seeing, a small degradation of System.nanoTime >could > have a big impact. > > Tomás > >On Tue, May 2, 2017 at 10:23 AM, Walter Underwood ><wun...@wunderwood.org> > wrote: > >> Hmm, has anyone measured the overhead of timeAllowed? We use it all >the > > time. > > > > If nobody has, I’ll run a benchmark with and without it. > > > > wunder > > Walter Underwood > > wun...@wunderwood.org >> >https://linkprotect.cudasvc.com/url?a=http://observer.wunderwood.org/&c=E,1,7uGY1VtJPqam-MhMKpspcb31C9NQ_Jh4nI0gzkQP4gVJkhcC5l031vMIHH0j38EdMESOM5Chjav3lUu1rpTdohTNTPdchTkl4TGNEHWJpJFJ-MR6RrjnTQ,,&typo=0 > (my blog) > > > > >> > On May 2, 2017, at 9:52 AM, Chris Hostetter ><hossman_luc...@fucit.org> > > wrote: > > > > > > > > > : I specify a timeout on all queries, .... > > > > > > Ah -- ok, yeah -- you mean using "timeAllowed" correct? > > > > > > If the root issue you were seeing is in fact clocksource related, > > > then using timeAllowed would probably be a significant compounding >> > factor there since it would involve a lot of time checks in a >single > > > request (even w/o any debugging enabled) > > > >> > (did your coworker's experiements with ES use any sort of >equivilent > > > timeout feature?) > > > > > > > > > > > > > > > > > > -Hoss >> > >https://linkprotect.cudasvc.com/url?a=http://www.lucidworks.com/&c=E,1,DwDibSb7PG6wpqsnn-u9uKdCuujyokjeyc6ero6bEdoUjs4Hn_X1jj_z6QAEDmorDqAP_TcaEJX8k5HYYJI7bJ7jQxTDpKUX9MvWAaP6ICoyVmpmQ8X7&typo=0 > > > > > -- Sorry for being brief. Alternate email is rickleir at yahoo dot com
