Re: time issues and ZFS

2013-01-27 Thread Adrian Chadd
On 26 January 2013 02:15, Andriy Gapon a...@freebsd.org wrote: on 23/01/2013 18:20 Adrian Chadd said the following: It may be a quirk of an older 9.x, which is fixed in -HEAD. It may be a quirk of the older generation celeron hardware - in which case, we need to tell the user somehow.. This

Re: time issues and ZFS

2013-01-27 Thread Andriy Gapon
on 27/01/2013 19:27 Adrian Chadd said the following: On 26 January 2013 02:15, Andriy Gapon a...@freebsd.org wrote: on 23/01/2013 18:20 Adrian Chadd said the following: It may be a quirk of an older 9.x, which is fixed in -HEAD. It may be a quirk of the older generation celeron hardware - in

Re: time issues and ZFS

2013-01-26 Thread Andriy Gapon
on 23/01/2013 18:20 Adrian Chadd said the following: It may be a quirk of an older 9.x, which is fixed in -HEAD. It may be a quirk of the older generation celeron hardware - in which case, we need to tell the user somehow.. This is not software related at all. It's the hardware feature (or

Re: time issues and ZFS

2013-01-23 Thread Andriy Gapon
on 22/01/2013 20:42 Adrian Chadd said the following: Hi! As I said before, the problem with non-HLT loops with event-timer in -9 and -head is that it calls the idle function inside a critical section (critical_enter and critical_exit) which blocks interrupts from occuring. The EI;HLT

Re: time issues and ZFS

2013-01-23 Thread Adrian Chadd
On 23 January 2013 06:58, Andriy Gapon a...@freebsd.org wrote: I don't think that this is true of x86 hardware in general. You might have hit some limitation or a quirk or a bug or an erratum for some particular hardware. E.g. a chipset on this machine has a bit described as such: Set to 1

Re: time issues and ZFS

2013-01-23 Thread John Nielsen
On Jan 22, 2013, at 2:40 AM, Adrian Chadd adr...@freebsd.org wrote: On Jan 21, 2013, at 4:33 AM, Daniel Braniss da...@cs.huji.ac.il wrote: host: DELL PowerEdge R710, 16GB, I administer a Dell PowerEdge R710 and I've been seeing the exact same thing. It's currently running FreeBSD

Re: time issues and ZFS

2013-01-23 Thread Daniel Braniss
On Jan 22, 2013, at 2:40 AM, Adrian Chadd adr...@freebsd.org wrote: On Jan 21, 2013, at 4:33 AM, Daniel Braniss da...@cs.huji.ac.il wrote: host: DELL PowerEdge R710, 16GB, I administer a Dell PowerEdge R710 and I've been seeing the exact same =thing. It's currently running FreeBSD

Re: time issues and ZFS

2013-01-22 Thread Adrian Chadd
Daniel, Have you run tests with the machdep.idle value changed, and fiddling kern.eventtimer.periodic / kern.eventtimer.idletick ? adrian ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To

Re: time issues and ZFS

2013-01-22 Thread Daniel Braniss
Daniel, Have you run tests with the machdep.idle value changed, and fiddling kern.eventtimer.periodic / kern.eventtimer.idletick ? Adrian, not yet, for several reasons: 1- as I explained, I can't realy force the problem, it happens when we run some zfs scripts, like mirror, but have to wait

Re: time issues and ZFS

2013-01-22 Thread Julian Stecklina
Thus spake Daniel Braniss da...@cs.huji.ac.il: In the meantime here is some info: Intel(R) Xeon(R) CPU E5645: running with no problems LAPIC(600) HPET(450) HPET1(440) HPET2(440) HPET3(440) i8254(100) RTC(0) Intel(R) Xeon(R) CPU X5550: this is the problematic, at least for the moment

Re: time issues and ZFS

2013-01-22 Thread Ryan Stone
On Tue, Jan 22, 2013 at 7:27 AM, Julian Stecklina jstec...@os.inf.tu-dresden.de wrote: Does anyone know why the LAPIC is given a lower priority than HPET in this case? If you have an LAPIC, it should always be prefered to HPET, unless something is seriously wrong with it... On many

Re: time issues and ZFS

2013-01-22 Thread Adam McDougall
On 01/22/13 07:27, Julian Stecklina wrote: Thus spake Daniel Braniss da...@cs.huji.ac.il: In the meantime here is some info: Intel(R) Xeon(R) CPU E5645: running with no problems LAPIC(600) HPET(450) HPET1(440) HPET2(440) HPET3(440) i8254(100) RTC(0) Intel(R) Xeon(R) CPU X5550: this is the

Re: time issues and ZFS

2013-01-22 Thread Adrian Chadd
Hi! As I said before, the problem with non-HLT loops with event-timer in -9 and -head is that it calls the idle function inside a critical section (critical_enter and critical_exit) which blocks interrupts from occuring. The EI;HLT instruction pair on i386/amd64 atomically and correctly handles

time issues and ZFS

2013-01-21 Thread Daniel Braniss
After many trials (and errors), here are some facts: host: DELL PowerEdge R710, 16GB, mfi0: Dell PERC H700 Integrated mfid0: 14305280MB (29297213440 sectors) RAID volume 'r5' is optimal mfi1: Dell PERC 6 mfid1: 12393472MB (25381830656 sectors) RAID volume 'Virtual Disk 0' is optimal we

Re: time issues and ZFS

2013-01-21 Thread Adrian Chadd
Hi, Try experimenting with kern.eventtimer.periodic and kern.eventtimer.idletick. If this fixes it for you, please file a PR with all the relevant details. Thanks! Adrian On 21 January 2013 03:33, Daniel Braniss da...@cs.huji.ac.il wrote: After many trials (and errors), here are some

Re: time issues and ZFS

2013-01-21 Thread Daniel Braniss
Hi, Try experimenting with kern.eventtimer.periodic and kern.eventtimer.idletick. can you give/point to some info about this? btw, I just noticed that on this hardware I get: 9.1-STABLE: vmstat -i interrupt total rate irq3: uart1 931

Re: time issues and ZFS

2013-01-21 Thread Ian Lepore
On Mon, 2013-01-21 at 13:33 +0200, Daniel Braniss wrote: After many trials (and errors), here are some facts: host: DELL PowerEdge R710, 16GB, mfi0: Dell PERC H700 Integrated mfid0: 14305280MB (29297213440 sectors) RAID volume 'r5' is optimal mfi1: Dell PERC 6 mfid1: 12393472MB

Re: time issues and ZFS

2013-01-21 Thread Daniel Braniss
... What's the output of sysctl kern.eventtimer? kern.eventtimer.periodic is 0 Does the bad behavior change if you set kern.eventimer.periodic=1? setting kern.eventtimer.timer=LAPIC instead of the default HPET made the missing cpu timers to

Re: time issues and ZFS

2013-01-21 Thread Ian Lepore
On Mon, 2013-01-21 at 17:35 +0200, Daniel Braniss wrote: ... What's the output of sysctl kern.eventtimer? kern.eventtimer.periodic is 0 Does the bad behavior change if you set kern.eventimer.periodic=1? setting

Re: time issues and ZFS

2013-01-21 Thread Adrian Chadd
I still firmly believe the ACPI event timer code is racy, and what we may be seeing here is the fallout from that. It's very possible that we're missing interrupts here - the new eventtimer code that made it into 9.x puts the halt behind a critical section, with interrupts disabled. The only

Re: time issues and ZFS

2013-01-21 Thread Daniel Braniss
I still firmly believe the ACPI event timer code is racy, and what we may be seeing here is the fallout from that. It's very possible that we're missing interrupts here - the new eventtimer code that made it into 9.x puts the halt behind a critical section, with interrupts disabled. The