Date: Sat, 26 Jan 2008 11:15:09 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Steven Hartland <killing@multiplay.co.uk> Cc: Chargen <chargen@gmail.com>, freebsd-current@freebsd.org Subject: Re: SMP kernels /w POLLING enabled - combination garbles(syncer?) console line message(s) on reboot Message-ID: <479B082D.4020309@FreeBSD.org> In-Reply-To: <003001c85fd9$03ea2e40$b6db87d4@multiplay.co.uk> References: <292361ab0801252036g75df6800x3b799aedaed02bde@mail.gmail.com> <003001c85fd9$03ea2e40$b6db87d4@multiplay.co.uk>
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Steven Hartland wrote:
> ----- Original Message ----- From: "Chargen" <chargen@gmail.com>
> To: <freebsd-current@freebsd.org>
> Sent: Saturday, January 26, 2008 4:36 AM
> Subject: 7cur: SMP kernels /w POLLING enabled - combination
> garbles(syncer?) console line message(s) on reboot
>
>
>> 7cur: SMP kernels /w POLLING enabled - combination garbles (syncer?)
>> console
>> line message(s) on reboot
>>
>> SMP kernel with POLLING enabled garbles one or more of the last lines in
>> console after issuing the {reboot} command
>>
>> options DEVICE_POLLING
>> options HZ=1000
>>
>> with or without sysctl -w kern.polling.enable=1 or sysctl -w
>> kern.polling.enable=0
>>
>> The garbled lines are between 'shutting down bufdaemon' and 'all buffs
>> synced' (after 'bufdaemon', I presume these are the syncer, 'Syncing
>> disks, vnodes synced' lines)
>>
>> I found it only reproducable with SMP /apic enabled kernel. Console
>> messages
>> after issuing reboot on UP kernels with polling_enabled are readable.
>>
>> Note: polling wasn't manually set on any device (tested on UP and SMP
>> kernels) e.g.: no ifconfig em0 polling
>
>
> Funny you should say that. Noticed that last night when rebooting one of
> our new 7.0 machines but assumed it was a one off remote console
> corruption.
>
> Just tested this again and its not. So I can confirm the corruption here
> on 7.0-PRERELEASE amd64 without polling.
It's harmless (actually a sign of increased concurrency); two threads
are running printf concurrently. Add options PRINTF_BUFR_SIZE=[...] if
you don't want to see this.
Kris
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