Re: [LAD] rtirq script is broken with 2.6.31

From: Rui Nuno Capela <rncbc@email-addr-hidden>
Date: Fri Aug 07 2009 - 19:50:33 EEST

Robin Gareus wrote:
> Rui Nuno Capela wrote:
>> Rui Nuno Capela wrote:
>>> Robin Gareus wrote:
>>>> Rui Nuno Capela wrote:
>>>>
>>>>> this issue on 2.6.31-rt has been already reported privately and i'll get
>>>>> to it as soon i get back home from vacation. meanwhile, it really looks
>>>>> like a regex trickery is all that's needed,
>>>> I'm not so sure, Since 2.6.31 it is also possible to raise the priority
>>>> not by IRQ number but by /device-driver/.
>>>>
>>>> ie:
>>>> PID CLS RTPRIO NI PRI %CPU STAT COMMAND
>>>> 9092 FF 89 - 129 0.4 S< irq/17-HDA Inte
>>>> 1447 FF 50 - 90 0.1 S< irq/17-uhci_hcd
>>>> 9093 FF 50 - 90 0.0 S< irq/17-ohci1394
>>>>
>>>> ..but of course that's also just regexp trickery ;)
>>>>
>>>> Note that the kernel limits the IRQ process name to 15 chars.
>>>> "HDA Inte" won't read "HDA Intel" even when using `ps -w..`
>>>>
>>>> But '/proc/interrupts' says:
>>>> 17: 17215454 873204 IO-APIC-fasteoi uhci_hcd:usb3, HDA Intel,
>>>> ohci1394
>>>>
>>>>> keeping in mind that
>>>>> backward compability with pre-2.6.31-rt kernels is in order (eg. i do
>>>>> still run on 2.56.29.5-rt22 for which the current rtirq script is
>>>>> perfect, of course)
>>>>> as a quick suggestion, try this for instance (re. line 120):
>>>>> PIDS=`ps -eo pid,comm | egrep "(IRQ.${IRQ}|irq\/${IRQ}\-.+)\$" | awk
>>>>> '{print $1}'`
>>>> That works, but raises all devices on a given IRQ-line and results in:
>>>> PID CLS RTPRIO NI PRI %CPU STAT COMMAND
>>>> 1447 FF 88 - 128 0.1 S< irq/17-uhci_hcd
>>>> 9092 FF 87 - 127 0.4 S< irq/17-HDA Inte
>>>> 9093 FF 86 - 126 0.0 S< irq/17-ohci1394
>>>>
>>> which is the exact and old behavior of rtirq for kernel-rt < 2.6.31-rt.
>>>
>>> this time however it looks that you can actually improve things when
>>> several device drivers are hanging on a irq line. that is, one can tune
>>> up the one and only the one actually intended (eg. "snd" => "irq/17-HDA
>>> Inte" and nothing else)
>>>
>>> not just a simple regex oneliner anymore and i'm afraid it might need a
>>> deeper retouch...
>>>
>> not so deeper, more than a simple regex fix but some bash trickery now
>> added: please, try the attached patch (rtirq-20090807-1.diff) and tell ;)
>
>
> Almost - it fails because "HDA Inte" has a space in it. So
> ${NAME2} is only "HDA" instead of "HDA Intel".
>
> I've added quotation marks around ${NAME2} to the rtirq_exec_num and
> rtirq_exec_name function calls (line 167 and line 231) and then it works.
>
> However, there's still an issue with RTIRQ_TRAIL. If one wants to raise
> two drivers on the same IRQ line. For example
> "HDA Intel" and "ohci1394" but not uhci_hcd:usb3 (all on IRQ 17 here)
> rtirq will only do the first device and skip the remaining.
>
> Thanks for your help, it must be fun to code on the beach ;)
>

beach support is fine ;)

here goes another one (rtirq-20090807-2.diff), with your quotation marks
in place and RTIRQ_TRAIL issue probably tamed ... please try as i don't
have the right kernel to make proper testing.

byee--off to snorkeling now 8)

-- 
rncbc aka Rui Nuno Capela
rncbc@email-addr-hidden


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Received on Fri Aug 7 20:15:06 2009

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