Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-Q5

Mark_H_Johnson_at_raytheon.com
Date: 08/31/04

  • Next message: Alan Cox: "Re: Driver retries disk errors." 
    To: Ingo Molnar <mingo@elte.hu>
Date:	Tue, 31 Aug 2004 07:46:08 -0500

    >in theory the patch is more or less equivalent to setting
    >netdev_max_backlog to a value of 1 - could you try that setting too?
    >(with the patch unapplied.)

    Ugh. That setting is VERY BAD. Just a quick test without
    doing anything complex...
      # echo 1 > /proc/sys/net/core/netdev_max_backlog
      # ping dws7
      PING dws7 (192.52.215.17) 56(84) bytes of data.
    [so the DNS lookup worked]
      From dws77... (192.52.215.87) icmp_seq=0 Destination Host Unreachable
      From dws77... (192.52.215.87) icmp_seq=1 Destination Host Unreachable
      From dws77... (192.52.215.87) icmp_seq=2 Destination Host Unreachable
      ...
    [NOTE - these are plugged into the same 10/100 Ethernet switch]
      # echo 8 > /proc/sys/net/core/netdev_max_backlog
      # ping dws7
      PING dws7 (192.52.215.17) 56(84) bytes of data.
    [so the DNS lookup worked]
      From dws77... (192.52.215.87) icmp_seq=0 ttl=64 time=2210 ms
      From dws77... (192.52.215.87) icmp_seq=1 ttl=64 time=1210 ms
      From dws77... (192.52.215.87) icmp_seq=2 ttl=64 time=210 ms
      From dws77... (192.52.215.87) icmp_seq=2 ttl=64 time=0.355 ms
      From dws77... (192.52.215.87) icmp_seq=2 ttl=64 time=0.397 ms
      ...
    I tried again with 2, 3, and 4. Two appears to be "way too small" with
    a ping of 1000 ms and nominal values of 0.800 ms. Three does not appear
    to be good either with nominal values of 0.500 ms. Four has similar
    results to eight (8).

    --Mark H Johnson
      <mailto:Mark_H_Johnson@raytheon.com>

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  • Next message: Alan Cox: "Re: Driver retries disk errors."