Re: Old SUN NFS performance papers.

From: Björn Grönvall (bg_at_sics.se)
Date: 01/27/04

  • Next message: Kris Kennaway: "Re: Old SUN NFS performance papers." 
    Date: Tue, 27 Jan 2004 20:17:58 +0100
To: Robert Watson <rwatson@freebsd.org>

    On Sat, 24 Jan 2004 21:14:51 -0500 (EST)
    Robert Watson <rwatson@freebsd.org> wrote:

    > I haven't done much benchmarking on NFS lately, but something worth
    > remembering is that people have spent a lot of time researching and
    > optimizing TCP for a variety of connection types, whereas the NFS code
    > basically has a static implementation of RPC backoff and flow control that
    > hasn't evolved much.

    One reason that FreeBSD users experience poor NFSv3/TCP performance is
    that the defaults for rsize and wsize is unusually small, only
    8k. Solaris and HP-UX defaults to 32k for a good reason. I guess TCP
    simply needs a little bit more data to chew on to be efficient.

    I tested this on 5.2-CURRENT and found that large file read
    performance went up from 56Mbit/s to 80Mbit/s, an improvement by 43%.

    I have written a patch that makes FreeBSD use the same defaults as
    Solaris and HP-UX. Note that with NFSv3 there is no risk associated
    with specifying to large values for [rw]size. The server automatically
    limits these values in the fsinfo rpc. Patch is attached.

    Cheers,
    Björn 

    -- 
  _     _                                           ,_______________.
Bjorn Gronvall (Björn Grönvall)                    /_______________/|
Swedish Institute of Computer Science              |               ||
PO Box 1263, S-164 29 Kista, Sweden                | Schroedingers ||
Email: bg@sics.se, Phone +46 -8 633 15 25          |      Cat      |/
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  • Next message: Kris Kennaway: "Re: Old SUN NFS performance papers."