Messages in this thread | | | From | Hayes Wang <> | Subject | RE: [PATCH net-next v2 2/3] r8152: cleartheflagofSCHEDULE_TASKLETintasklet | Date | Mon, 10 Nov 2014 05:23:14 +0000 |
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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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