Find the answer to your Linux question:
Results 1 to 5 of 5
I'm trying to improve performance on one of my machines (a web server, with 4 CPU cores). Here's the output of vmstat 3: Code: procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ ...
Enjoy an ad free experience by logging in. Not a member yet? Register.
  1. #1
    Just Joined!
    Join Date
    Mar 2007
    Posts
    19

    Interpreting vmstat output


    I'm trying to improve performance on one of my machines (a web server, with 4 CPU cores). Here's the output of vmstat 3:

    Code:
    procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
     r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
     0  3  62284 1540400 234200 3283712    1    2     5   151   20   29 17  1 39 43  0
     3  3  62284 1535716 234200 3283712    0    0     0    44 1565  627  9  1 42 48  0
     1  3  62284 1540312 234200 3283712    0    0     0     0 1517  489 18  1 38 43  0
     0  3  62284 1539792 234200 3283712    0    0     0    85 1216  275  3  0 47 50  0
     1  3  62284 1539420 234200 3283712    0    0     0     0 1171  238  3  0 47 50  0
     1  3  62284 1540696 234200 3283712    0    0     0    36 2113 1197 32  1 27 39  0
     0  3  62284 1541680 234200 3283712    0    0     0   128 1365  348  9  0 43 47  0
     0  3  62284 1539308 234200 3283716    0    0     0    67 1420  555 14  1 43 42  0
     0  3  62284 1543268 234204 3283712    0    0     0   731 1914  898  7  1 44 49  0
     0  3  62284 1543640 234204 3283716    0    0     0     0 1151  163  1  0 49 50  0
     1  3  62284 1539316 234204 3283716    0    0     0    33 1536  696 12  1 39 48  0
     0  3  62284 1545020 234204 3283716    0    0     0     0 1161  163  6  0 46 48  0
     0  3  62284 1542468 234208 3283680    0    0     0   148 1395 1862 19 14 33 34  0
     0  3  62284 1542708 234208 3283684    0    0     0   405 1407  477  4  1 46 50  0
     2  3  62284 1543264 234208 3283688    0    0     0     0 1789  943 22  1 39 38  0
     0  3  62284 1541032 234208 3283688    0    0     0   141 1824  994 13  2 39 46  0
     1  3  62284 1533600 234208 3283688    0    0     0     0 1490  594 19  1 40 40  0

    I'm curious about those 3 blocking processes. Disk IO is pretty low (the machine has 8 GB of RAM, so plenty of caching going on) and the CPU seems to be spending around half its time waiting.

    Any suggestion on how to interpret this?

    How would I go about tracking down those blocking processes?

  2. #2
    Linux Guru coopstah13's Avatar
    Join Date
    Nov 2007
    Location
    NH, USA
    Posts
    3,149
    is your web server running just apache or are you running some kind of application server? Additionally you can get disk information with iostat -d -x where you can see the actual IO and verify that isn't the problem.

  3. #3
    Just Joined!
    Join Date
    Mar 2007
    Posts
    19
    Thanks for the reply. I tried iostat, but it didn't really shed any light. I'd previously run hdparm -tT, and the disk performance is great, so I'm still baffled as to the blocking processes

  4. #4
    Linux Guru coopstah13's Avatar
    Join Date
    Nov 2007
    Location
    NH, USA
    Posts
    3,149
    What are you using for a web server? Are you using a database in the back end?

  5. #5
    Just Joined!
    Join Date
    May 2011
    Posts
    12
    linux performance tuning commands, uptime,top,mpstat,iostat,vmstat ,free,ping,Dstat Tutorial
    .youtube.com/watch?v=Si0qwjhFbZ4

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •