Re: 2.6.12 Performance problems

From: Ben Greear (greearb_at_candelatech.com)
Date: 08/25/05

  • Next message: Hiro Yoshioka: "Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()" 
    Date:	Wed, 24 Aug 2005 21:51:57 -0700
To: danial_thom@yahoo.com

    Danial Thom wrote:

    > I think the concensus is that 2.6 has made trade
    > offs that lower raw throughput, which is what a
    > networking device needs. So as a router or
    > network appliance, 2.6 seems less suitable. A raw
    > bridging test on a 2.0Ghz operton system:
    >
    > FreeBSD 4.9: Drops no packets at 900K pps
    > Linux 2.4.24: Starts dropping packets at 350K pps
    > Linux 2.6.12: Starts dropping packets at 100K pps

    I ran some quick tests using kernel 2.6.11, 1ms tick (HZ=1000), SMP kernel.
    Hardware is P-IV 3.0Ghz + HT on a new SuperMicro motherboard with 64/133Mhz
    PCI-X bus. NIC is dual Intel pro/1000. Kernel is close to stock 2.6.11.

    I used brctl to create a bridge with the two GigE adapters in it and
    used pktgen to stream traffic through it (250kpps in one direction, 1kpps in
    the other.)

    I see a reasonable amount of drops at 250kpps (60 byte packets):
    about 60,000,000 packets received, 20,700 dropped.

    Interestingly, the system is about 60% idle according to top,
    and still dropping pkts, so it would seem that the system could
    be better utilized!

    Ben 

    -- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com
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  • Next message: Hiro Yoshioka: "Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()"