Date: Mon, 14 Jan 2002 13:01:41 -0700 (MST) From: Alex Rousskov <rousskov@measurement-factory.com> To: Terry Lambert <tlambert2@mindspring.com> Cc: net@FreeBSD.ORG Subject: Re: 64 bit counters again Message-ID: <Pine.BSF.4.10.10201141239410.7315-100000@measurement-factory.com> In-Reply-To: <3C432F3A.FE136FD@mindspring.com>
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On Mon, 14 Jan 2002, Terry Lambert wrote: > This is getting way off topic, but here is a business case > illustration. > > Are you perhaps doing what the Q/A people at a previous job were > doing, and stress-testing the crap out of a machine on a Gigabit > LAN, at or near wire speeds, when in the field, the equipment is > *NEVER*, *EVER* going to have to handle anywhere near even 1/40th > of the load you are placing on it? <snip> > In fact, this assumes linear amplification: "multiply the data > rate by 40, and you multiply the failure rate by 40"; in the > real world, this relationship is exponential: something you see > at the stress breaking point of your product will be almost > impossible to repeat in the field. In my experience, this logic and conclusion do not hold in general. Yes, there are cases where beating the crap out of a machine is useless. However, in many cases, stress-testing at performance limits is one of the fastest and simplest ways of finding bugs that would otherwise be exposed under real (and possibly less stressful) conditions. And not just performance-related bugs, I must add! This kind of testing is never sufficient, of course. Disclaimer: I beat the crap out of machines for a living. This probably makes me biased (but Terry is probably biased the other way around since it is "his" box that is being beaten). This also makes me exposed to real-world cases where beating has been very useful... Alex. P.S. I am not implying that 32 bit counters is a bug. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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