<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">>> I think I get the pro of using threaded interrupts - to decrease the maximum<br>
>> interrupt latency on RT workloads and/or RT machines (servers, embedded,<br>
>> etc.).<br>
>> So, I'd like to ask:<br>
>> - Why not **all** of the drivers use the threaded interrupts?<br>
>> - What are the cons of the threaded interrupts?<br>
>><br>
> Just a wild assumption: maybe the cost of incurring context switches ?<br>> (comparing to tasklets)<br><br>I get that threaded IRQ is better than softIrqs because threaded IRQ supports<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">priorities. On the other hand, added context switches surely get system slower.<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">But from the practical point of view - why on relatively new Intel PC there are<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">no threaded irqs at all?<br><br>```<br>$ uname -a<br>Linux kostaz-OptiPlex-7010 3.19.0-26-generic #28-Ubuntu SMP Tue Aug 11 14:16:32 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux<br>```<br><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">--- KostaZ<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Sep 10, 2015 at 11:09 PM, Rami Rosen <span dir="ltr"><<a href="mailto:roszenrami@gmail.com" target="_blank">roszenrami@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Kosta,<br>
<br><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"></div>
Just a wild assumption: maybe the cost of incurring context switches ?<br>
(comparing to tasklets)<br>
<br>
Best Regards,<br>
Rami Rosen<br>
<a href="http://ramirose.wix.com/ramirosen" rel="noreferrer" target="_blank">http://ramirose.wix.com/ramirosen</a><br>
<div><div class="h5"><br>
<br>
<br>
On 10 September 2015 at 20:49, Kosta Zertsekel <<a href="mailto:zertsekel@gmail.com">zertsekel@gmail.com</a>> wrote:<br>
> Hi guys,<br>
><br>
> I hope I'm on right mailing list. :-)<br>
> I think I get the pro of using threaded interrupts - to decrease the maximum<br>
> interrupt latency on RT workloads and/or RT machines (servers, embedded,<br>
> etc.).<br>
><br>
> Also, I see that in 4.2 there are only ~76 drivers that use threaded<br>
> interrupt:<br>
> ```<br>
> $ git grep -l IRQ_WAKE_THREAD | sort | grep -v "\.h" | wc -l<br>
> 76<br>
> ```<br>
><br>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"></div>> So, I'd like to ask:<br>
> - Why not **all** of the drivers use the threaded interrupts?<br>
> - What are the cons of the threaded interrupts?<br>
><br>
> Thanks,<br>
> --- KostaZ<br>
><br>
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</blockquote></div><br></div></div>