Date: Mon, 21 Apr 2003 17:35:59 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: rizzo@icir.org Cc: freebsd-hackers@freebsd.org Subject: Re: wi(4) - polling(4) changes / DEVICE_POLLING Message-ID: <20030421.173559.43009491.imp@bsdimp.com> In-Reply-To: <20030421064717.B98117@xorpc.icir.org> References: <20030421130029.A29555-100000@foem.leiden.webweaving.org> <20030421064717.B98117@xorpc.icir.org>
next in thread | previous in thread | raw e-mail | index | archive | help
In message: <20030421064717.B98117@xorpc.icir.org>
Luigi Rizzo <rizzo@icir.org> writes:
: if i remember well, the "wi" driver copies the packet from the card
: to the mbuf using programmed I/O. Switching to polling will just
: move the load under a different bucket (SYSTEM or IDLE instead
: of INTR) but not change the situation radically, and i
: doubt you will achieve significant performance improvements.
The wi driver does use PIO to move the data from the cards to memory.
Newer PCI and mini-pci cards support using DMA to do this, but there's
no support for that in the driver at the moment.
The wi cards are just damn expensive to talk to :-(.
Warner
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20030421.173559.43009491.imp>