Messages in this thread | | | Date | Fri, 18 Aug 2006 14:23:56 -0500 | Subject | Re: [PATCH 2/4]: powerpc/cell spidernet low watermark patch. | From | (Linas Vepstas) |
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On Thu, Aug 17, 2006 at 01:43:40AM +0200, Benjamin Herrenschmidt wrote: > > Sounds good (without actually looking at the code though :), that was a > long required improvement to that driver. Also, we should probably look > into using NAPI polling for tx completion queue as well, no ?
Just for a lark, I tried using NAPI polling, while disabling all TX interrupts. Performance was a disaster: 8Mbits/sec, fom which I conclude that the tcp ack packets do not flow back fast enough to allw reliance on NAPI polling for transmit.
I was able to get as high as 960 Mbits/sec in unusal circumstances, at 100% cpu usage. Oprofile indicates that the next major improvement would be to add scatter/gather, which I'll take a shot at next week, if I don't get interrupted. However, I'm getting interrupted a lot these days.
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