From: Stephen Hemminger <shemminger@vyatta.com>
To: Mark Ryden <markryde@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: request_threaded_irq()
Date: Fri, 12 Nov 2010 08:35:26 -0800 [thread overview]
Message-ID: <20101112083526.1c3784b1@nehalam> (raw)
In-Reply-To: <AANLkTikCQRiW3oWYSXK7yTxLWd3us+8wdwfuOs1k71VD@mail.gmail.com>
On Fri, 12 Nov 2010 14:27:11 +0200
Mark Ryden <markryde@gmail.com> wrote:
> Hello netdev,
>
> grepping under net-next-2.6/drivers/net for request_threaded_irq() ,
> shows that it appears only in 3 drivers:
>
> can/mcp251x.c
> wireless/b43/main.c
> wireless/rt2x00/rt2x00pci.c
>
> I was wondering: when thinking about performance, is it worthwhile to use this
> API instead of ordinary request_irq() . It seems to me that
> request_threaded_irq() might
> be better in some cases than NAPI polling forr network drivers (or at
> list it might be so in some systems, maybe multicore ?)
Threaded irq is not needed for properly written NAPI driver.
A NAPI driver should do minimum work in real irq and the whole NAPI processing
will happen in soft-irq.
There has been discussion of moving NAPI softirq into a high
priority thread. But last time I tried it, the performance was noticably
worse on network intensive benchmarks.
prev parent reply other threads:[~2010-11-12 16:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-12 12:27 request_threaded_irq() Mark Ryden
2010-11-12 16:35 ` Stephen Hemminger [this message]
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