Re: [PATCH 2/5] forcedeth: interrupt handling cleanup

Yinghai Lu
2007-10-07T19:37:06Z

On 10/7/07, Jeff Garzik <jeff@garzik.org> wrote:
> Yinghai Lu wrote:
> > On 10/6/07, Jeff Garzik <jeff@garzik.org> wrote:
> >> commit a606d2a111cdf948da5d69eb1de5526c5c2dafef
> >> Author: Jeff Garzik <jeff@garzik.org>
> >> Date: Fri Oct 5 22:56:05 2007 -0400
> >>
> >> [netdrvr] forcedeth: interrupt handling cleanup
> >>
> >> * nv_nic_irq_optimized() and nv_nic_irq_other() were complete duplicates
> >> of nv_nic_irq(), with the exception of one function call. Consolidate
> >> all three into a single interrupt handler, deleting a lot of redundant
> >> code.
> >>
> >> * greatly simplify irq handler locking.
> >>
> >> Prior to this change, the irq handler(s) would acquire and release
> >> np->lock for each action (RX, TX, other events).
> >>
> >> For the common case -- RX or TX work -- the lock is always acquired,
> >> making all successive acquire/release combinations largely redundant.
> >>
> >> Acquire the lock at the beginning of the irq handler, and release it at
> >> the end of the irq handler. This is simple, easy, and obvious.
> >>
> >> * remove irq handler work loop.
> >>
> >> All interesting events emanating from the irq handler either have
> >> their own work loops, or they poke a timer into action.
> >>
> >> Therefore, delete the pointless master interrupt handler work loop.
> >>
> >> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
> >>
> Do you have ideas/suggestions for a different method?

in the e1000 driver, it has seperate handler for msi and ioapic.

but in forcedeth, the nv_nic_irq_optimized keep check msi_flags...,
with num of msi interrupt number, that could cause cpu loading get a
little bit high..., even the network performance is ok.

YH