Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 22 Feb 2003 18:05:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 22 Feb 2003 18:05:49 -0500 Received: from bitmover.com ([192.132.92.2]:32428 "EHLO mail.bitmover.com") by vger.kernel.org with ESMTP id ; Sat, 22 Feb 2003 18:05:48 -0500 Date: Sat, 22 Feb 2003 15:15:52 -0800 From: Larry McVoy To: "Martin J. Bligh" Cc: Larry McVoy , Mark Hahn , "David S. Miller" , linux-kernel@vger.kernel.org Subject: Re: Minutes from Feb 21 LSE Call Message-ID: <20030222231552.GA31268@work.bitmover.com> Mail-Followup-To: Larry McVoy , "Martin J. Bligh" , Larry McVoy , Mark Hahn , "David S. Miller" , linux-kernel@vger.kernel.org References: <1510000.1045942974@[10.10.2.4]> <20030222195642.GI1407@work.bitmover.com> <2080000.1045947731@[10.10.2.4]> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2080000.1045947731@[10.10.2.4]> User-Agent: Mutt/1.4i X-MailScanner: Found to be clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3573 Lines: 67 On Sat, Feb 22, 2003 at 01:02:12PM -0800, Martin J. Bligh wrote: > > How much do you want to bet that more than 95% of their server revenue > > comes from 4CPU or less boxes? I wouldn't be surprised if it is more > > like 99.5%. And you can configure yourself a pretty nice quad xeon box > > for $25K. Yeah, there is some profit in there but nowhere near the huge > > margins you are counting on to make your case. > > OK, so now you've slid from talking about PCs to 2-way to 4-way ... > perhaps because your original arguement was fatally flawed. Nice attempt at deflection but it won't work. Your position is that there is no money in PC's only in big iron. Last I checked, "big iron" doesn't include $25K 4 way machines, now does it? You claimed that Dell was making the majority of their profits from servers. To refresh your memory: "I bet they still make more money on servers than desktops and notebooks combined". Are you still claiming that? If so, please provide some data to back it up because, as Mark and others have pointed out, the bulk of their servers are headless desktop machines in tower or rackmount cases. I fail to see how there are better margins on the same hardware in a rackmount box for $800 when the desktop costs $750. Those rack mount power supplies and cases are not as cheap as the desktop ones, so I see no difference in the margins. Let's get back to your position. You want to shovel stuff in the kernel for the benefit of the 32 way / 64 way etc boxes. I don't see that as wise. You could prove me wrong. Here's how you do it: go get oprofile or whatever that tool is which lets you run apps and count cache misses. Start including before/after runs of each microbench in lmbench and some time sharing loads with and without your changes. When you can do that and you don't add any more bus traffic, you're a genius and I'll shut up. But that's a false promise because by definition, fine grained threading adds more bus traffic. It's kind of hard to not have that happen, the caches have to stay coherent somehow. > Some applications work well on clusters, which will give them cheaper > hardware, at the expense of a lot more complexity in userspace ... > depending on the scale of the system, that's a tradeoff that might go > either way. Tell it to Google. That's probably one of the largest applications in the world; I was the 4th engineer there, and I didn't think that the cluster added complexity at all. On the contrary, it made things go one hell of a lot faster. > You don't believe we can make it scale without screwing up the low end, > I do believe we can do that. I'd like a little more than "I think I can, I think I can, I think I can". The people who are saying "no you can't, no you can't, no you can't" have seen this sort of work done before and there is no data which shows that it is possible and all sorts of data which shows that it is not. Show me one OS which scales to 32 CPUs on an I/O load and run lmbench on a single CPU. Then take that same CPU and stuff it into a uniprocessor motherboard and run the same benchmarks on under Linux. The Linux one will blow away the multi threaded one. Come on, prove me wrong, show me the data. -- --- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/