lkml.org 
[lkml]   [2007]   [Oct]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] forcedeth: fix the NAPI poll function
Ingo Molnar wrote:
> * Jeff Garzik <jeff@garzik.org> wrote:
>
>>> FYI, looks good so far, ontop of Linus' latest -git tree.
>>>
>>> btw., one thing i always found weird about forcedeth is that it
>>> generates an extra ~100 irqs per second even when there's no network
>>> traffic:
>>>
>>> 11: 89752 XT-PIC-XT eth0
>>> 11: 89854 XT-PIC-XT eth0
>>> 11: 89955 XT-PIC-XT eth0
>>> 11: 90056 XT-PIC-XT eth0
>>> 11: 90157 XT-PIC-XT eth0
>>>
>>> (irq count snapshot every second). Just in case it's easy to fix ...
>>
>> May I presume that behavior occurs in both mainline and my fe-lock
>> branch?
>
> correct.

Any chance of getting a quick comparison of forcedeth CPU usage in your
setup, between old driver and fe-lock driver?

I'm curious about the effects of fe-lock on CPU usage, which NAPI is
known to perturb (in positive or negative directions, depending on
conditions).

I presume both drivers can work at wire speed, sans any "too many
iterations" problems...


>> That is likely the NIC's timer irq, which is programmed to kick the
>> irq handler every so often. DEV_NEED_TIMERIRQ is a starting point, as
>> well as "Known bugs" at the top of forcedeth.c, if you're curious.
>>
>> I'm _betting_ that some of that can be eliminated, but we'll see...
>
> ok. Was just a FYI - you were looking for feedback :-)

Thanks! :)

Jeff


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-16 18:55    [W:0.074 / U:0.356 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site