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I'm running the FLOW3 Quickstart on a Fedora machine (virtualized on Windows, if that helps). Each and every single request takes about 1.2 seconds to run the most simple example of this framework. I ran top and was expecting to see some CPU or I/O wait but instead, the machine seems to be just waiting for something, with an hardward IRQ at 100%:

top - 13:21:42 up 57 min,  3 users,  load average: 3.49, 2.05, 1.29
Tasks: 147 total,   2 running, 145 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,  0.0%id,  0.0%wa,100.0%hi,  0.0%si,  0.0%st
Mem:    768208k total,   485356k used,   282852k free,     5524k buffers
Swap:  1507324k total,    19424k used,  1487900k free,   102724k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
 2315 apache    20   0  102m  24m  10m S  2.3  3.2   0:00.82 httpd              
 2316 apache    20   0  102m  24m  10m S  1.7  3.2   0:00.86 httpd              
 2319 apache    20   0  102m  24m  10m S  1.7  3.3   0:00.78 httpd              
 1734 test      20   0 73688  12m 7388 S  0.7  1.6   0:16.96 gnome-terminal     
 1041 root      20   0 70788  27m 2496 S  0.3  3.7   0:31.71 Xorg               
 2472 apache    20   0 23160 5104 3712 R  0.3  0.7   0:00.01 php                
    1 root      20   0  5208 1932 1464 S  0.0  0.3   0:01.11 systemd            
    2 root      20   0     0    0    0 S  0.0  0.0   0:00.00 kthreadd           
    3 root      20   0     0    0    0 S  0.0  0.0   0:00.75 ksoftirqd/0        
    6 root      RT   0     0    0    0 S  0.0  0.0   0:00.00 migration/0        
    7 root      RT   0     0    0    0 S  0.0  0.0   0:00.08 watchdog/0         
    8 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 cpuset             
    9 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 khelper            
   10 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 netns              
   11 root      20   0     0    0    0 S  0.0  0.0   0:00.00 sync_supers        
   12 root      20   0     0    0    0 S  0.0  0.0   0:00.00 bdi-default        
   13 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kintegrityd    

Software versions: Fedora 15, PHP 5.3.6, MySQL 5.6.2-m5

Information: a simple <?php phpinfo(); ?> script runs in 5ms.

Any idea where this hardware IRQ is coming from??

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What type of virtualization are you using? –  Dana the Sane Sep 8 '11 at 18:17
    
@Dana: VirtualBox –  Benjamin Sep 8 '11 at 19:00

1 Answer 1

up vote 1 down vote accepted

Sounds like the delay stems from the overhead incurred by virtual box to host your vm. I think that you will see this delay disappear if you switch to another virtualization solution (Hyper-V, Xen, KVM, VMWare, etc).

I believe that virtual box isn't designed to offer low latency access to hardware, just a convenient container for guest OS's (at the expense of performance).

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Thanks for you answer, isn't it possible to see which (virtual) hardware is interrupting the CPU? –  Benjamin Sep 8 '11 at 20:41

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