High Apache CPU Load

Discussion in 'Apache' started by komodo, Mar 26, 2009.

0
  1. #1
    Hi,

    I've search around quite a bit, but I can't seem to find a clear answer.

    I've turned on mod_status, and on the status page, I'm worried Apache is being overworked.

    CPU Usage: u334.883 s94.5703 cu177.422 cs0 - 43.3% CPU load
54.1 requests/sec - 181.5 kB/second - 3435 B/request
178 requests currently being processed, 52 idle workers

__RKKK__K___KW_CKCKC_KC_KCK_KKCCK_K_KKWCKCCKCWKKKCRCKKKK._K_C__K
KK_K__K_K_KK_C_KKKKK_KKW.KRCKWKKW_CCKWKRK..___KKCKKKKKKKR_KKKW.W
_KK_____RKRC.KKCKCCRK__CK._KWCK_KKRCCK.C__CR.CWCCKCRKK.RR.K_CR_K
C_KW._._K.K..KKK_KRCCKWKK__..R.CRWCKK.KCK.K.KK_K....._...KK.....
......KC.CK...C...CK......W........C............................
................................................................
................................................................
................................................................
    Code (markup):
    At the time I took this particular snapshot, it's not near its peak... it's not uncommon for the CPU load approach 60%. Reading around, it seems the CPU load should normally be under 1% (such as 0.0139% or what-not). Is this true?

    The weird thing though... I have no idea where that number is coming from, because according to "top", the CPU is actually 90% idle.

    Here is my Apache MPM settings:

    ServerLimit 512
<IfModule mpm_prefork_module>
    StartServers         10
    MinSpareServers      15
    MaxSpareServers      50
    MaxClients         1024
    MaxRequestsPerChild   0
</IfModule>
    Code (markup):
    I actually just raised the MaxClients from 512 to 1024 because I was hitting a constant cap of 40 requests/sec... and I was worried it was going to bottleneck. When I raised that value, the max requests per second now seem to be freed up.

    If the actual CPU of the server is 90% idle... am I okay? Anyone know where Apache's getting the CPU Load info from? Any recommendations for optimization?

    Thanks everyone!
     
    komodo, Mar 26, 2009 IP
  2. ~kev~

    ~kev~ Well-Known Member

    Messages:
    2,866
    Likes Received:
    194
    Best Answers:
    0
    Trophy Points:
    110
    #2
    What kind of site are you running - blog, forum or something else?

    Have you checked your traffic with google analytics or some other kind of traffic tool? I would start by taking a look at your traffic. And use a tool that directly measures traffic.

    If your site has a lot of graphics, that might explain heavy load. How big are the pages your site is loading?
     
    ~kev~, Mar 26, 2009 IP
  3. komodo

    komodo Well-Known Member

    Messages:
    379
    Likes Received:
    10
    Best Answers:
    0
    Trophy Points:
    123
    #3
    It's a multimedia site.... and I do track traffic using Google Analytics.
    We employee a CDN however, so the pages on loaded from this server are fairly small (but there are a lot of them).
     
    komodo, Mar 26, 2009 IP
  4. ultrasonic

    ultrasonic Peon

    Messages:
    30
    Likes Received:
    2
    Best Answers:
    0
    Trophy Points:
    0
    #4
    What are your server specs, and what scripts are you using and what programs do they use (ie. mysql?)? How much traffic are you currently getting?
     
    ultrasonic, Apr 3, 2009 IP
  5. shalafiraist

    shalafiraist Peon

    Messages:
    131
    Likes Received:
    0
    Best Answers:
    0
    Trophy Points:
    0
    #5
    it's mostly because of your MPM settings and to find the right values, you have to play on the values and test.

    also try disabling keep alives. With high visitor numbers, apache's keep alive can mess the things out.
     
    shalafiraist, Apr 3, 2009 IP