[LAD] rtirq script is broken with 2.6.31

[Rui Nuno Capela]

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 ;)

cheers
-- 
rncbc aka Rui Nuno Capela
rncbc at rncbc.org
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