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SubjectRE: [PATCH net-next v2 2/3] r8152: cleartheflagofSCHEDULE_TASKLETintasklet
Date
 Francois Romieu [mailto:romieu@fr.zoreil.com] 
> Sent: Sunday, November 09, 2014 6:12 AM
[...]
> The performance explanation leaves me a bit unconvinced. Without any
> figure one could simply go for the always locked clear_bit because of:
> 1. the "I'm racy" message that the open-coded test + set sends
> 2. the extra work needed to avoid 1 (comment, explain, ...).

Thanks. I would modify this patch with clear_bit only.

> The extra time could thus be used to see what happens when napi is
> shoehorned in this tasklet machinery. I'd naively expect it to be
> relevant for efficiency.

I thought about NAPI, but I gave up. The reasons are
1. I don't sure if it would run when autosuspending.
2. There is no hw interrupt for USB device. And I have
no idea about how to check if the USB transfer is
completed by polling.
3. I have to control the rx packets numbers in poll().
However, I couldn't control the packets number for
each bulk-in transfer. I have to do extra works to
deal with the rx flow.
4. I don't find much different between tasklet and NAPI.

Best Regards,
Hayes


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