Taylor R Campbell writes:
[snip]
> Can you try the attached patch on a dom0 and see if you still observe
> drift?
I had a little time to mess with trying 10.99.6 on the DOM0.. I applied
your patch to 10.99.6 and built a XEN3_DOM0 kernel (XEN3_DOM0 + bigger
IFQ_MAXLEN). The result was, while
Taylor R Campbell writes:
> [1:text/plain Hide]
>
>> Date: Tue, 01 Aug 2023 16:02:17 -0400
>> From: Brad Spencer
>>
>> Taylor R Campbell writes:
>>
>> > So I just added a printf to the kernel in case this jump happens. Can
>> > you update to xen_clock.c 1.15 (and sys/arch/x86/include/cpu.h 1
> Date: Tue, 01 Aug 2023 16:02:17 -0400
> From: Brad Spencer
>
> Taylor R Campbell writes:
>
> > So I just added a printf to the kernel in case this jump happens. Can
> > you update to xen_clock.c 1.15 (and sys/arch/x86/include/cpu.h 1.135)
> > and try again?
>
> Sure...
Correction: xen_cloc
Taylor R Campbell writes:
>> Date: Mon, 31 Jul 2023 12:47:20 -0400
>>
>> # dtrace -x nolibs -n 'sdt:xen:hardclock:jump { @ = quantize(arg1 - arg0) }
>> sdt:xen:hardclock:jump /arg2 >= 430/ { printf("hardclock jump violated
>> timecounter contract") }'
>> dtrace: description 'sdt:xen:hardclock:
> Date: Mon, 31 Jul 2023 12:47:20 -0400
>
> # dtrace -x nolibs -n 'sdt:xen:hardclock:jump { @ = quantize(arg1 - arg0) }
> sdt:xen:hardclock:jump /arg2 >= 430/ { printf("hardclock jump violated
> timecounter contract") }'
> dtrace: description 'sdt:xen:hardclock:jump ' matched 2 probes
> dtrace:
Taylor R Campbell writes:
>> Date: Sun, 30 Jul 2023 14:56:53 -0400
>> From: Brad Spencer
>>
>> Taylor R Campbell writes:
>>
>> > Can you please try running with the attached patch and share the
>> > warnings it produces? Should give slightly more information.
>>
>> Caught another one. As f
> Date: Sun, 30 Jul 2023 14:56:53 -0400
> From: Brad Spencer
>
> Taylor R Campbell writes:
>
> > Can you please try running with the attached patch and share the
> > warnings it produces? Should give slightly more information.
>
> Caught another one. As far as I know the system is up to date
Taylor R Campbell writes:
> Can you please try running with the attached patch and share the
> warnings it produces? Should give slightly more information.
Caught another one. As far as I know the system is up to date with all
of the requested patches:
[ 19419.647972] WARNING: lwp 16 (system
> Date: Fri, 28 Jul 2023 09:42:30 -0400
> From: Brad Spencer
>
> Thanks, that allowed the dtrace to execute, but I never have time to
> execute the second probe, as this kernel panic occures within a few
> seconds of the first probe being run (probably on the order of 4 - 5
> seconds):
>
> [ 213
Taylor R Campbell writes:
>> Date: Fri, 28 Jul 2023 07:42:04 -0400
>> From: Brad Spencer
>>
>> dtrace: invalid probe specifier sdt:xen:hardclock:jump { @ = quantize(arg1 -
>> arg0) } tick-10s { printa(@) }: probe description :::tick-10s does not match
>> any probes
>
> modload dtrace_profile
Taylor R Campbell writes:
>> Date: Fri, 28 Jul 2023 07:42:04 -0400
>> From: Brad Spencer
>>
>> dtrace: invalid probe specifier sdt:xen:hardclock:jump { @ = quantize(arg1 -
>> arg0) } tick-10s { printa(@) }: probe description :::tick-10s does not match
>> any probes
>
> modload dtrace_profile
> Date: Fri, 28 Jul 2023 07:42:04 -0400
> From: Brad Spencer
>
> dtrace: invalid probe specifier sdt:xen:hardclock:jump { @ = quantize(arg1 -
> arg0) } tick-10s { printa(@) }: probe description :::tick-10s does not match
> any probes
modload dtrace_profile
Taylor R Campbell writes:
>> Date: Thu, 27 Jul 2023 11:17:30 -0400
>> From: Brad Spencer
>>
>> On the system that I have that exhibits the negative runtime problem, it
>> may very well be the case that hardclocks are missed for 4.3sec. The
>> system has to have been up for a while and busy as
> Date: Thu, 27 Jul 2023 11:17:30 -0400
> From: Brad Spencer
>
> On the system that I have that exhibits the negative runtime problem, it
> may very well be the case that hardclocks are missed for 4.3sec. The
> system has to have been up for a while and busy as a prereq., but if I
> then run:
>
Taylor R Campbell writes:
[snip]
> I don't know what the sparc timecounter frequency is, but the Xen
> system timecounter returns units of nanoseconds, i.e., runs at 1 GHz,
> well within these bounds. So this kind of wraparound leading to
> apparently negative runtime -- that is, l->l_stime goi
> Date: Thu, 27 Jul 2023 15:05:23 +1000
> from: matthew green
>
> one problem i've seen in kern_tc.c when the timecounter returns
> a smaller value is that tc_delta() ends up returning a very large
> (underflowed) value, and that makes the consumers of it do a very
> wrong thing. eg, -2 becomes
Taylor R Campbell writes:
> Can you please try running with the attached patch and share the
> warnings it produces? Should give slightly more information.
I applied the patch and caught this:
[ 76783.161208] WARNING: lwp 16 (system idle/1) flags 0xa020: timecounter
went backwards from (7
one problem i've seen in kern_tc.c when the timecounter returns
a smaller value is that tc_delta() ends up returning a very large
(underflowed) value, and that makes the consumers of it do a very
wrong thing. eg, -2 becomes 2^32-2, and then eg in binuptime:
477 bintime_addx(bt, th
Can you please try running with the attached patch and share the
warnings it produces? Should give slightly more information.
>From b6f360d9b1fdc418105fcc41b41f1206ca04334d Mon Sep 17 00:00:00 2001
From: Taylor R Campbell
Date: Wed, 26 Jul 2023 01:36:28 +
Subject: [PATCH] WIP: attribution for
Taylor R Campbell writes:
>> Date: Thu, 20 Jul 2023 21:50:26 -0400
>> From: Brad Spencer
>>
>> With a DOMU kernel compiled with KDTRACE_HOOKS I get the following with
>> either of those dtrace probes on the DOMU:
>>
>> dtrace -n 'sdt:xen:clock:, sdt:xen:hardclock:, sdt:xen:timecounter: {
>> p
Taylor R Campbell writes:
>> Date: Thu, 20 Jul 2023 21:50:26 -0400
>> From: Brad Spencer
>>
>> With a DOMU kernel compiled with KDTRACE_HOOKS I get the following with
>> either of those dtrace probes on the DOMU:
>>
>> dtrace -n 'sdt:xen:clock:, sdt:xen:hardclock:, sdt:xen:timecounter: {
>> p
Taylor R Campbell writes:
>> Date: Thu, 20 Jul 2023 21:50:26 -0400
>> From: Brad Spencer
>>
>> With a DOMU kernel compiled with KDTRACE_HOOKS I get the following with
>> either of those dtrace probes on the DOMU:
>>
>> dtrace -n 'sdt:xen:clock:, sdt:xen:hardclock:, sdt:xen:timecounter: {
>> p
Taylor R Campbell writes:
>> Date: Thu, 20 Jul 2023 21:50:26 -0400
>> From: Brad Spencer
>>
>> With a DOMU kernel compiled with KDTRACE_HOOKS I get the following with
>> either of those dtrace probes on the DOMU:
>>
>> dtrace -n 'sdt:xen:clock:, sdt:xen:hardclock:, sdt:xen:timecounter: {
>> p
> Date: Thu, 20 Jul 2023 21:50:26 -0400
> From: Brad Spencer
>
> With a DOMU kernel compiled with KDTRACE_HOOKS I get the following with
> either of those dtrace probes on the DOMU:
>
> dtrace -n 'sdt:xen:clock:, sdt:xen:hardclock:, sdt:xen:timecounter: {
> printf("%d %d %d %d %d %d %d", arg0,
Taylor R Campbell writes:
>> Date: Sat, 08 Jul 2023 14:34:56 -0400
>> From: Brad Spencer
>>
>> Taylor R Campbell writes:
>>
>> > Can you either:
>>
>> Yes, I can perform as much of this as needed after I get some other
>> stuff in life dealt with more towards the end of the month. I really
> Date: Thu, 13 Jul 2023 13:39:43 +
> From: Taylor R Campbell
>
> > Date: Sat, 08 Jul 2023 14:34:56 -0400
> > From: Brad Spencer
> >
> > [ 1792486.921759] kobj_checksyms, 988: [dtrace]: linker error: symbol
> > `dtrace_invop_calltrap_addr' not found
> > [ 1792486.921759] kobj_checksyms, 98
> Date: Sat, 08 Jul 2023 14:34:56 -0400
> From: Brad Spencer
>
> Taylor R Campbell writes:
>
> > Can you either:
>
> Yes, I can perform as much of this as needed after I get some other
> stuff in life dealt with more towards the end of the month. I really
> won't have any time before then.
N
Taylor R Campbell writes:
>> Date: Wed, 04 Jan 2023 14:43:25 -0500
>> From: Brad Spencer
>>
>> So... I have a PV+PVSHIM DOMU running a pretty recent 9.x on a DOM0
>> running a 9.99.xx kernel. The DOM0 is not large, a 4 processor E-2224
>> with 32GB of memory. The DOMU has 2 VCPUs and 8GB of
> Date: Wed, 04 Jan 2023 14:43:25 -0500
> From: Brad Spencer
>
> So... I have a PV+PVSHIM DOMU running a pretty recent 9.x on a DOM0
> running a 9.99.xx kernel. The DOM0 is not large, a 4 processor E-2224
> with 32GB of memory. The DOMU has 2 VCPUs and 8GB of memory. About
> every day a very
So... I have a PV+PVSHIM DOMU running a pretty recent 9.x on a DOM0
running a 9.99.xx kernel. The DOM0 is not large, a 4 processor E-2224
with 32GB of memory. The DOMU has 2 VCPUs and 8GB of memory. About
every day a very particular DOMU tosses the:
WARNING: negative runtime; monotonic clock
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