> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of David Miller > Sent: Wednesday, January 23, 2008 11:30 PM > > From: Andi Kleen <[EMAIL PROTECTED]> > Date: Thu, 24 Jan 2008 08:25:49 +0100 > > > > have done away with handling tx completion in the interrupt handler, > and > > > are instead handling them in the context of the transmit. The slow > path, > > > straggling transmit completions will be handled in the timer context. > > > > Ok -- hopefully you don't have bad corner cases from this when the pipe > > is not fully filled and then causing longer latencies on completion. > > Old NAPI sometimes suffered from such problems. > > BTW, such a TX completion timer will stall TCP sockets when the TX > queue of the device is partially filled and then sending stops. > > TX ring SKB liberation really must be done in a very small finite > amount of time in order to avoid this problem properly. > > Deferring it to HZ granular timers doesn't give a quick enough > response, especially at high packet rates. [Ram] We could add a lower granular tx completion interrupt instead, to handle all the transmit fifos. But this will be a fall back in the event the completions do not happen in the context of the transmit.
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