zombies with AMD64 and 32 bit userspace with 2.6

From: David Lang (david.lang_at_digitalinsight.com)
Date: 05/15/04

  • Next message: Greg KH: "Re: [PATCH] Driver Core patches for 2.6.6" 
    To: linux-kernel@vger.kernel.org
Date:	Fri, 14 May 2004 16:24:43 -0700 (PDT)

    I have a box I am testing in my lab which is a dual opteron with a
    complete 32 bit userspace (debian based) with a 64 bit kernel. when
    running a stress test with a highly forking workload I am running into a
    situation where it generates a lot of zombies

    the test is a simple forking proxy that receives connections from one
    machine (running apache benchmark) and forwards them to anothr machine
    (running apache). for <~30,000 requests the machine keeps up with no
    problem (apache is the bottlneck here at ~3500 requests/sec), but if I try
    to do a test with more then about 30,000 requests in it the box starts to
    generate zombie processes (eventually running into the max processes limit
    and stopping)

    the smaller tests leave no zombies at all and can be run multiple times
    without a problem (although I have not run them back to back, so there is
    a substantial bit of time between tests)

    I have been able to duplicate this with the 2.6.4 and 2.6.6 kernels.

    running the exact same test (same binaries except for the kernel) on a
    dual athlon box has no problems (the dual athlon box becomes the
    bottleneck at ~2500 connections/sec) and has survived 10,000,000
    connection tests.

    David Lang 

    -- 
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan
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  • Next message: Greg KH: "Re: [PATCH] Driver Core patches for 2.6.6"

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