http://oliverp.teteny.bme.hu/freebsd/ktr/
On 4/29/12, Alexander Motin <m...@freebsd.org> wrote: > On 04/29/12 15:04, Oliver Pinter wrote: >> Removing dummynet from kernel don't chanage anything, that is releated >> to load average. The loadavg hold to 0.70 +/- 0.2. (single user : sh + >> top) > > New ktr dump? > >> On 4/29/12, Alexander Motin<m...@freebsd.org> wrote: >>> On 04/29/12 09:09, Ian Smith wrote: >>>> On Sun, 29 Apr 2012 08:17:38 +0300, Alexander Motin wrote: >>>> > On 04/29/12 01:53, Oliver Pinter wrote: >>>> > > Attached the ktr file. This is on core2duo P9400 cpu ( >>>> > > smbios.system.product="HP ProBook 5310m (WD792EA#ABU)" ). >>>> The >>>> workload >>>> > > is only a single user boost: sh + top running, but the load >>>> average is >>>> > > near 0.5. >>>> > >>>> > ktr shows no real load there. But it shows that you are using >>>> dummynet, that >>>> > schedules its runs on every hardclock tick. I believe that load >>>> you >>>> see is >>>> > the result or synchronization between dummynet calls and loadvg >>>> sampling, >>>> > both of which called from hardclock. I think removing dummynet >>>> from >>>> equation, >>>> > should hide this problem and also reduce you laptops power >>>> consumption. >>>> > >>>> > What's about fixing this, it is loadavg sampling algorithm that >>>> should be >>>> > changed. Fixing dummynet to not run on every hardclock tick >>>> would >>>> also be >>>> > great. >>>> >>>> Wading in out of my depth, and copying Luigi in case he misses it .. >>>> but >>>> even back in the olden days when HZ defaulted to 100, one was advised >>>> to >>>> use HZ>= 1000 for smooth dummynet traffic shaping dispatch scheduling. >>>> >>>> I wonder, with the newer clocks and timers, whether there is another >>>> clock that could be used for dummynet scheduling, that would not have >>>> this effect (even if largely cosmetic?) on load average calculation? >>> >>> First of all, the easiest solution would be to make dummynet to schedule >>> callout not automatically, but on first queued packet. I believe that in >>> case of laptop the queue should be empty most of time and the callout >>> calls are completely useless there. Luigi promised to look on this once. >>> >>> What's about better precision/removing synchronization -- there is >>> starting GSoC project now (by davide@) to rewrite callout(9) subsystem >>> to use better precision allowed by new timer drivers. While now it is >>> possible to get raw access to additional timer hardware available on >>> some systems, I don't think it is a good idea. > > > -- > Alexander Motin > _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
