netdev - Re: request_threaded

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20101112083526.1c3784b1@nehalam>
Date:	Fri, 12 Nov 2010 08:35:26 -0800
From:	Stephen Hemminger <shemminger@...tta.com>
To:	Mark Ryden <markryde@...il.com>
Cc:	netdev@...r.kernel.org
Subject: Re: request_threaded_irq()

On Fri, 12 Nov 2010 14:27:11 +0200
Mark Ryden <markryde@...il.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.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html