From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 28 Apr 2003 05:42:24 -0700 From: Fred Gray To: Gabriel Paubert Cc: linuxppc-dev@lists.linuxppc.org Subject: Re: ppc_irq_dispatch_handler dominating profile? Message-ID: <20030428124224.GC26408@socrates.berkeley.edu> References: <20030427194236.GC25907@socrates.berkeley.edu> <16044.23965.747962.112267@nanango.paulus.ozlabs.org> <20030428085342.GA7396@iram.es> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20030428085342.GA7396@iram.es> Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Mon, Apr 28, 2003 at 10:53:42AM +0200, Gabriel Paubert wrote: > Hmmm, I get more than 100MB/s on my MVME2600 with a 200MHz 603e, > although not the half GB/s Motorola claims it is capable of. But a 604 > should be a bit faster. The chipset is old (1997) but it was rather > fast when it came out, especially because the memory interface is 128 > bits wide. This said, putting a gbit Ethernet (PMC module I suppose) > on it is stretching it a bit. > > Is the 100Mb/s of the builtin interface too slow for you? Hi, Gabriel, (...and many thanks for your hard work porting Linux to these boards in the first place--I am extremely glad to be in a position to leave vxWorks behind) The gigabit Ethernet is indeed on a PMC module (from SBS Technologies, PMC-Gigabit-ST3). Our electronics generates about 15 MB/s per VME crate; it's digitizing tracks left by muons in a time-projection chamber. There are two crates, each with this rate, each equipped with an MVME2600 with an gigabit card, and they have to transfer this firehose of data to a computer that will do some as-yet-undefined online data reduction and send the result to an LTO 2 tape robot. So, yes, we need about 50% more throughput than the built-in 10/100 Ethernet port could provide, and we need it with enough CPU time left over to manage the VME readout. Fortunately, though, we don't need the whole gigabit. I agree that would probably be well-nigh impossible. Still, I'm very interested in understanding why the interrupt overhead seems to be so high at our 10 to 15 MB/s interrupt rate. Thanks, -- Fred -- Fred Gray / Visiting Postdoctoral Researcher -- -- Department of Physics / University of California, Berkeley -- -- fegray@socrates.berkeley.edu / phone 510-642-4057 / fax 510-642-9811 -- ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/