DSCHED and interbench

[Venkatesh Srinivas <me@xxxxxxxxxxxxxxxxxxx>]

Hi,

Just have some numbers for interbench comparing dsched none to dsched FQ.

These numbers are from a 12/31/2010 kernel, on an Atom N270 running an SMP kernel. The disk was an ata/100 disk connected via a USB bridge.

Interbench 
dsched noop

(Audio)
Test    Latency/SD (ms) Max latency    % cpu    % deadlines hit
None  0.03 +/- 0.0306    0.057              100         100
Video 0.045 +/- 0.033     8.04                100         100

X        0.033 +/- 0.033     0.074              100         100
Burn  0.051 +/- 0.266      6.45                100         100
Write  2.55 +/- 13.5         119                  98.5        97.8
Read  0.132 ++/ 1.09      26.5                 100         100

Compile 2.67 +/- 13.4     131                   99          98.7
Memload 2.41 +/- 29.6    634                  96.6        96.6

(Video)
Test    Latency/SD (ms) Max latency    % cpu    % deadlines hit
None  0.06 +/- 0.88         33.4                99.9        99.9
X        0.097 +/- 1.86       65.9                 99.8        99.8
Burn  33.7 +/- 93.6          535                  45.1         43.4
Write  3.03 +/- 11.7         169                  89.2        86.9
Read  0.108 +/- 0.87       36.2                 99.9        99.9
Compile 25.8 +/- 60.7      434                  49.6       40.1
Memload 1.69 +/- 23.8    603                  95.3        94.7

dsched fq

(Audio)
Test    Latency/SD (ms) Max latency    % cpu    % deadlines hit
None  0.087 +/- 1.06      24.2                100         100
Video 0.076 +/- 0.598     10.4                100         100
X        0.195 +/- 3.91       95.7                100         99.8
Burn  0.095 +/- 0.778      13.6                100         100
Write  2.1 +/- 10.8           134                  99.2        99
Read  0.128 +/- 0.655     11.4                 100         100
Compile 1.13 +/- 4.65      28.9                 100         100
Memload 2.54 +/- 19.5     309                  95.8        95.8

(Video)
Test    Latency/SD (ms) Max latency    % cpu    % deadlines hit

None  0.087 +/- 2.26       95.8                 99.8        99.8
X        0.14 +/- 1.57         28.3                 100         100
Burn  36.7 +/- 103           615                  42.6        40.9

Write  2.97 +/- 12            217                  90.1        87.8

Read  0.11 +/- 0.99         33.8                 99.8        99.8

Compile 29.8 +/- 76.2      608                  46.3       38.4

Memload 1.25 +/- 14.1    317                  95.4        94.5

More numbers from disabling bioqdisksort() and some discussion will follow, but just wanted to put these out.

-- vs