IBM REDP-4285-00 User Manual
4285ch02.fm
Draft Document for Review May 4, 2007 11:35 am
74
Linux Performance and Tuning Guidelines
netserver
, generates network traffic, gets the result from
netserver
via a control connection
which is separated from the actual benchmark traffic connection. During the benchmarking,
no communication occurs on the control connection so it does not have any effect on the
result. The netperf benchmark tool also has a reporting capability including a CPU utilization
report. The current stable version is 2.4.3 at the time of writing.
no communication occurs on the control connection so it does not have any effect on the
result. The netperf benchmark tool also has a reporting capability including a CPU utilization
report. The current stable version is 2.4.3 at the time of writing.
netperf
can generate several types of traffic. Basically these fall into the two categories: bulk
data transfer traffic and request/response type traffic. One thing you should keep in mind is
netperf uses only one socket at a time. The next version of netperf (netperf4) will fully support
benchmarking for concurrent session. At this time, we can perform multiple session
benchmarking as described below.
netperf uses only one socket at a time. The next version of netperf (netperf4) will fully support
benchmarking for concurrent session. At this time, we can perform multiple session
benchmarking as described below.
Bulk data transfer
Bulk data transfer is most commonly measured factor when it comes to network
benchmarking. The bulk data transfer is measured by the amount of data transferred in
one second. It simulates large file transfer such as multimedia streaming, FTP data
transfer.
benchmarking. The bulk data transfer is measured by the amount of data transferred in
one second. It simulates large file transfer such as multimedia streaming, FTP data
transfer.
Request/response type
This simulate request/response type traffic which is measured by the number of
transactions exchanged in one second. Request/response traffic type is typical for online
transaction application such as web server, database server, mail server, file server which
serves small or medium files and directory server. In real environment, session
establishment and termination should be performed as well as data exchange. To simulate
this, TCP_CRR type was introduced.
transactions exchanged in one second. Request/response traffic type is typical for online
transaction application such as web server, database server, mail server, file server which
serves small or medium files and directory server. In real environment, session
establishment and termination should be performed as well as data exchange. To simulate
this, TCP_CRR type was introduced.
Concurrent session
netperf
does not have real support for concurrent multiple session benchmarking in the
current stable version, but we can perform some benchmarking by just issuing multiple
instances of netperf as follows:
instances of netperf as follows:
for i in ‘seq 1 10‘; do netperf -t TCP_CRR -H target.example.com -i 10 -P 0
&; done
&; done
We’ll take a brief look at some useful and interesting options.
Global options:
-A
Change send and receive buffer alignment on remote system
-b
Burst of packet in stream test
-H
<remotehost>
Remote host
-t
<testname>
Test traffic type
TCP_STREAM
Bulk data transfer benchmark
TCP_MAERTS
Similar to TCP_STREAM except direction of stream is opposite.
TCP_SENDFILE
Similar to TCP_STREAM except using sendfile() instead of
send()
send()
. It causes a zero-copy operation.
UDP_STREAM
Same as TCP_STREAM except UDP is used.
TCP_RR
Request/response type traffic benchmark
TCP_CC
TCP connect/close benchmark. No request and response packet is
exchanged.
exchanged.
TCP_CRR
Performs connect/request/response/close operation. It’s very much
like HTTP1.0/1.1 session with HTTP keepalive disabled.
like HTTP1.0/1.1 session with HTTP keepalive disabled.
UDP_RR
Same as TCP_RR except UDP is used.