Re: FreeBSD-11.0-CURRENT on ARM: performance and load average
On Sat, 2014-09-20 at 22:44 +0400, Maxim V FIlimonov wrote: Hello everyone, Recently, I encountered a problem with -CURRENT on an ARM board (cubieboard2 to be precise). The problem was that the load average was above 2. Including the fact that the board has 2 CPU cores, that's strange. Also, the network throughput was way too slow: from 3 kilobytes per second earlier to 20..50 about now. Here's a workaround for that: sysctl kern.eventtimer.periodic=1 With that, the network performance increased while LA decreased to a decent 0.3..0.5. Since it's happening only on that hardware, there's a good chance the problem is in the allwinner a10/a20 clock driver, not in the general eventtimer code. In fact, looking at the code it appears that a divide-by-16 is being set in the hardware, but not accounted for when setting the frequency of the eventtimer. Hmm, it should affect the timecounter too, in which case you'd see time-of-day advancing 16x too fast. If ntpd is running it would need to step the clock pretty frequently, which would show up in syslog. I don't have hardware to test on, please see if the attached patch makes a difference. -- Ian Index: sys/arm/allwinner/timer.c === --- sys/arm/allwinner/timer.c (revision 271909) +++ sys/arm/allwinner/timer.c (working copy) @@ -199,7 +199,7 @@ a10_timer_attach(device_t dev) val |= TIMER_ENABLE; timer_write_4(sc, SW_TIMER_IRQ_EN_REG, val); - sc-timer0_freq = SYS_TIMER_CLKSRC; + sc-timer0_freq = SYS_TIMER_CLKSRC / 16; /* Set desired frequency in event timer and timecounter */ sc-et.et_frequency = sc-timer0_freq; ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
Re: FreeBSD-11.0-CURRENT on ARM: performance and load average
On Saturday 20 September 2014 13:24:08 Ian Lepore wrote: Since it's happening only on that hardware, there's a good chance the problem is in the allwinner a10/a20 clock driver, not in the general eventtimer code. In fact, looking at the code it appears that a divide-by-16 is being set in the hardware, but not accounted for when setting the frequency of the eventtimer. Hmm, it should affect the timecounter too, in which case you'd see time-of-day advancing 16x too fast. If ntpd is running it would need to step the clock pretty frequently, which would show up in syslog. I'm running FreeBSD-current on the board right now, the time is just fine. I don't have hardware to test on, please see if the attached patch makes a difference. Well, it did: with the patch applied, the time ran about 60 times as fast as it should have. I didn't notice any changes with load average, though: maybe it's because I forgot to turn that sysctl setting I set before back to 0. wbr, Maxim Filimonov c...@bein.link ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
Re: FreeBSD-11.0-CURRENT on ARM: performance and load average
* Maxim V FIlimonov (c...@bein.link) wrote: Recently, I encountered a problem with -CURRENT on an ARM board (cubieboard2 to be precise). The problem was that the load average was above 2. Including the fact that the board has 2 CPU cores, that's strange. Also, the network throughput was way too slow: from 3 kilobytes per second earlier to 20..50 about now. Here's a workaround for that: sysctl kern.eventtimer.periodic=1 With that, the network performance increased while LA decreased to a decent 0.3..0.5. I'm just started to experiment with cubieboard (1) as well. I've also noticed poor network performance at first, however later (without any tuning) it gave out 111 kBps. kern.eventtimer.periodic doesn't seem to affect it. I've also played with clocks a bit, and was able to increase CPU rate 3x by configuring PLL1. I've experienced some instability later (board doesn't always boot from USB, perl build fails), and now I'm checking if reclocking was the cause. -- Dmitry Marakasov . 55B5 0596 FF1E 8D84 5F56 9510 D35A 80DD F9D2 F77D amd...@amdmi3.ru ..: jabber: amd...@jabber.ruhttp://www.amdmi3.ru ___ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to freebsd-current-unsubscr...@freebsd.org
