Yinghai Lu wrote:
On 10/7/07, Jeff Garzik <[email protected]> wrote:
Yinghai Lu wrote:
On 10/6/07, Jeff Garzik <[email protected]> wrote:
commit a606d2a111cdf948da5d69eb1de5526c5c2dafef
Author: Jeff Garzik <[email protected]>
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 <[email protected]>
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.
With all the activity in the interrupt handler, a few in-cache branches
are definitely going to be lost in the noise.
Separating the interrupt handlers between MSI and non-MSI tends to be of
more benefit when the separation is accompanied by more efficient
locking in the MSI interrupt handler, or a different mode of interrupt
clear, or some other attribute.
Though CPU usage would be a good thing to measure, with these patches.
Jeff
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