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High Apache load jump for no apparent reason

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  • High Apache load jump for no apparent reason

    [EDIT] Problem solved, see the next post.

    Hi I am working on setting up my vBulletin test site for public release tomorrow. At the moment there are no active users on my website, just two admins working. I encountered a strange problem yesterday - every page on website got much slower than before, Apache load to process every page increased significantly. Trying to pinpoint the issue, I looked at Debugging Info table. There is a big gap in time spent between two requests:

    Datastore Setup:
    Time Before: 0.00348 seconds
    Time After: 0.03787 seconds
    Time Taken: 0.03439 seconds
    Memory Before: 233.430 KB
    Memory After: 2,178.645 KB
    Memory Used: 1,945.215 KB
    Notice the huge jump in memory consumption. And then the very next request:
    Session Handling:
    Time Before: 4.82031 seconds
    Time After: 4.82092 seconds
    Time Taken: 0.00061 seconds
    Memory Before: 2,420.191 KB
    Memory After: 2,420.102 KB
    Memory Used: -0.090 KB
    Where did my 4.8 seconds go?
    Just a couple of days ago the whole page was processed in under 2 seconds.

    Some site information:
    vBulletinĀ® 3.8.0 Beta 2
    Lots of mods are installed, but no new mods added recently. One custom built component was slightly modified yesterday - may be just a coincidence.
    Webserver: Apache 2.2.8
    PHP (Apache module): PHP 5.2.4
    cat /proc/meminfo
    MemTotal:      2074584 kB
    MemFree:         78552 kB
    Buffers:         77536 kB
    Cached:        1731528 kB
    SwapCached:         52 kB
    Active:        1103964 kB
    Inactive:       830804 kB
    HighTotal:     1178560 kB
    HighFree:        17116 kB
    LowTotal:       896024 kB
    LowFree:         61436 kB
    SwapTotal:     1951888 kB
    SwapFree:      1951772 kB
    Dirty:              64 kB
    Writeback:           0 kB
    AnonPages:      125648 kB
    Mapped:          40388 kB
    Slab:            50248 kB
    SReclaimable:    38052 kB
    SUnreclaim:      12196 kB
    PageTables:       2552 kB
    NFS_Unstable:        0 kB
    Bounce:              0 kB
    CommitLimit:   2989180 kB
    Committed_AS:   393956 kB
    VmallocTotal:   118776 kB
    VmallocUsed:      4584 kB
    VmallocChunk:   113992 kB
    HugePages_Total:     0
    HugePages_Free:      0
    HugePages_Rsvd:      0
    HugePages_Surp:      0
    Hugepagesize:     2048 kB
    [email protected]:~$ cat /proc/cpuinfo
    processor       : 0
    vendor_id       : GenuineIntel
    cpu family      : 15
    model           : 2
    model name      : Intel(R) Pentium(R) 4 CPU 2.40GHz
    stepping        : 9
    cpu MHz         : 2411.643
    cache size      : 512 KB
    fdiv_bug        : no
    hlt_bug         : no
    f00f_bug        : no
    coma_bug        : no
    fpu             : yes
    fpu_exception   : yes
    cpuid level     : 2
    wp              : yes
    flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe up pebs bts cid xtpr
    bogomips        : 4826.65
    clflush size    : 64
    The attached screenshot shows what happens to the system when a vBulletin page is requested.

    Does anyone have an idea what could be the reason?
    Attached Files
    Last edited by crkgb; Sun 16 Nov '08, 12:54pm.

  • #2
    Problem found. By turning on and off different mods we singled out the guilty party - the front page slideshow. It was putting acceptable load on server in test mode when there were just 3 news to display, but it went totally out of hand after we added content and it was rotating 10 news articles. So the bad deal is that we lost a good looking part of our main page. The good deal is that now our pages get processed really fast - from 0.4 to 0.8 seconds


    widgetinstance 262 (Related Topics) skipped due to lack of content & hide_module_if_empty option.