Re: [PATCH] Re: 2.1.xxx makes Electric Fence 22x slower

Dean Gaudet (dgaudet-list-linux-kernel@arctic.org)
Wed, 9 Sep 1998 20:27:03 -0700 (PDT)


On Fri, 4 Sep 1998, Linus Torvalds wrote:

> However, I'm not at all convinced that "efence slows down" is an argument
> at all - I want to hear some _real_ applications slow down rather than
> debugging code.

I'm sorry, but efence is a real application. By analogy, one of the
greatest things about purify on sparc was that I was able to take a MUD,
with 30+Mb of data, and run it live, with 150 players. That's purify, and
sparc. I've never tried that particular app with efence on linux. My
point is that purify had a 50% performance degredation on that app, and
that was sufferable and allowed us to find a rather nasty problem that
only popped up under heavy usage.

efence can be used in similar situations provided you've got the RAM for
it... and if you've knocked it down by an order of magnitude or so then
you've made it useless... which degrades linux as a debugging platform.

At any rate, has anyone tried using Apache 1.3's mod_mmap_static in this
situation? It's in the modules/experimental directory. I suggest mmaping
a few thousand files and accessing them randomly.

Dean

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