lighty's life

For 1.5.0 I added fcgi-stat-accel to svn and to the cmake build.

I want to on port 1029 as a first test round. The -C 1 is to start only one thread in the back to see the impact later.

$ ./build/spawn-fcgi -f ./build/fcgi-stat-accel -p 1029 -C 1

As config on lighttpd side we have to enable X-Sendfile and keep a few connections open in the pool.

$SERVER["socket"] == ":1025" {
  $HTTP["url"] =~ "^/seek-bound/" {
    proxy-core.protocol = "fastcgi" 
    proxy-core.backends = ( "127.0.0.1:1029" )
    proxy-core.allow-x-sendfile = "enable" 
    proxy-core.max-pool-size = 20
  }
}

As test-env I used 100k files as in the other tests (10G of data over all).

$ http_load -parallel 200 -seconds 60 urls.100k

iostat said:

$ iostat -xm 5
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           9.20    0.00   45.80   45.00    0.00    0.00

Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await  svctm  %util
sda          0.00   0.00 73.00  0.00 13278.40    0.00     6.48     0.00   181.90     7.09   98.30  13.71 100.08
sdb          0.00   0.00 69.20  0.00 12625.60    0.00     6.16     0.00   182.45    13.63  194.71  14.46 100.08

We are limited by the disks now, perhaps we can reduce the CPU usage a bit more by using unix domain sockets instead of TCP:

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           8.19    0.00   38.56   53.25    0.00    0.00

Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await  svctm  %util
sda          0.00   1.00 67.63  4.30 12533.07   47.95     6.12     0.02   174.91    10.28  144.44  13.89  99.90
sdb          0.00   1.00 66.13  4.30 12442.76   47.95     6.08     0.02   177.35    11.92  168.46  14.18  99.90

The system time drops by 6, good enough.

Summary

Thanks to Fobax great idea I can finally max out my two disks. If you have more disks the impact will be a lot larger. Give it a try.

name             Throughput    util%
----------------- ------------- ---------
no stat-accel     12.07MByte/s 81%
stat-accel (tcp)  13.64MByte/s 99%
stat-accel (unix) 13.86MByte/s 99%