Re: [PATCH 2/4]: powerpc/cell spidernet low watermark patch.

From: linas@austin.ibm.com (Linas Vepstas)
Date: Fri, 18 Aug 2006 14:23:56 -0500

On Thu, Aug 17, 2006 at 01:43:40AM +0200, Benjamin Herrenschmidt wrote:

quoted

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.

The idea is to use NAPI polling with TX interrupts disabled.

We're not saying to use the RX interrupt as the trigger for
RX and TX work.  Rather, either of RX or TX interrupt will
schedule the NAPI poll.