Bandwidth testing: Difference between revisions

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==Units==
For these measurements:
* 1 kB/s = 1,000 bytes per second
* 1 mB/s = 1,000,000 bytes per second
* 1 gB/s = 1,000,000,000 bytes per second
==Machines tested==
==Machines tested==



Revision as of 16:08, 13 May 2010

Units

For these measurements:

  • 1 kB/s = 1,000 bytes per second
  • 1 mB/s = 1,000,000 bytes per second
  • 1 gB/s = 1,000,000,000 bytes per second

Machines tested

machine
name
processor
speed
memSize10 files
of size
dd /dev/zero
to /dev/shm
cp /dev/shm
to /tmp
cp /dev/shm
to hive
rsync /dev/shm
to /dev/shm
hgwdevOpteron
1150 Mhz
32 Gb1 gB800 mB/s287 mB/s54 mB/s144 mB/s
kolossusIntel
2261 Mhz
1 Tb1 gB1980 mB/s192 mB/s41 mB/s120 mB/s
4X rsync
okazakiIntel
1600 Mhz
2 Gb76 mB700 mB/s90 mB/s11.3 mB/s11.5 mB/s
mitzieIntel
400 Mhz
512 Kb18 mB113 mB/s25 mB/sn/a 37 kB/s up
down

Procedure

Sizing files based on available /dev/shm space. Largest file size limited to 1 gB.

The /dev/zero to /dev/shm write is done ten times with a dd command:

 dd if=/dev/zero of=/dev/shm/memToMem.$I.zero bs=200000 count=$ddCount

The /dev/shm copy to /tmp is done ten times with the cp command:

cp -p /dev/shm/memToMem.$I.zero ./memToFile.$I.zero

These 10X copies were repeated three times. The slowest measurement of the three times was recorded.

The rsync /dev/shm to /dev/shm was to and from hgwdev. Multiple instances of rsync from kolossus to hgwdev seemed to add together for a total bandwidth higher than a single instance of rsync.

The machine mitzie is at the end of a Santa Cruz DSL line and over a WiFi network connection across the driveway to the garage.