Re: fdesc allocation optimization

From: Dag-Erling Smørgrav (des_at_des.no)
Date: 08/22/05

  • Next message: Andre Oppermann: "Re: fdesc allocation optimization" 
    To: Alexey Dokuchaev <danfe@FreeBSD.org>
Date: Mon, 22 Aug 2005 15:32:22 +0200

    Alexey Dokuchaev <danfe@FreeBSD.org> writes:
    > i've been browsing some of dfbsd resources recently, and found this one
    > being pretty interesting:
    >
    > http://leaf.dragonflybsd.org/mailarchive/commits/2005-06/msg00526.html
    >
    > however, it seemingly did not get attention in our lists. so i am
    > wondering if there are work/plans on porting hsu@'s work? i remember
    > that at some point we adopted some openbsd-derived algorithm, but since
    > matt states that this is "far better algorithm then anything we or
    > freebsd thought up before", i figured it worth a look.

    Bollocks. Our current algorithm (which I wrote) is so fast you don't
    even notice it's there. It's actually simpler than the OpenBSD code
    from which it was inspired, and in theory it should be slower, but I
    discovered that the overhead of the "better" algorithm was so high
    that it consistently lost to the simpler one for reasonable amounts of
    file descriptors (up to about 100,000 per process).

    The source code for the microbenchmark I used, and selected graphs
    comparing my code to the previous implementation, are available at
    <URL:http://people.freebsd.org/~des/fdbench/>.

    (the strange artifacts you see on the red graphs are the result of the
    file descriptor table overrunning the CPU cache)

    DES 

    -- 
Dag-Erling Smørgrav - des@des.no
_______________________________________________
freebsd-arch@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-arch
To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org"
  • Next message: Andre Oppermann: "Re: fdesc allocation optimization"