Stories

From NetLogger

If you have used NetLogger to track done a hard to find problem and have some nice figures demonstrating before and after results, please send them to us.

Some old examples can be found here: http://dsd.lbl.gov/NetLogger-nonwiki/results.html

Here you can find a collection of previous NetLogger results, including log files, nlv-keys files, and sample screen dumps. If you are trying to figure out how to display your data in NLV, looking at these examples should give you some ideas.

Contents 1 Example 1: Amber and Ganglia 2 Example 2: Remote IO application (DPSS) 3 Example 3: FTP application (Globus GridFTP) 4 Example 4: Visualization of Remote Data 5 Example 5: Network Monitoring (NTAF) 6 Example 6: Web100 Monitoring (iperf) 7 Additional examples

Example 1: Amber and Ganglia

• Description: Data From Amber application (SC2003 demo). Includes CPU data.
• Screen dumps: nlv results
• Download: raw data and nlv_keys files

Example 2: Remote IO application (DPSS)

• Description: This shows the results for a NetLogger Analysis of High Energy Physics analysis application (STAF) doing a remote read of data on a DPSS server. The blue, green, and brown lines are tracing a data read request as it is send to the remote server. The lines fan out as a single read request on the client get split into multiple disk reads on the server. In this case data resided on 4 DPSS servers, hence the 4 colors of lines. The red lines show what is happening inside of the STAF application. "PAM" is a CPU intensive operation, shown at the top of the screen. What we learned from this plot was that this application spent about twice as much time doing data analysis as it spent doing remote IO. Overlapping I/O and computation would result in a large increase in performance.
• Screen dumps: Remote IO application screen dumps
• Download: raw data and nlv_keys files

Example 3: FTP application (Globus GridFTP)

• Description: This is an example of using NetLogger to analyze and debug the Globus GridFTP program. These results are client side only. Note the large overhead (about 9 seconds) of the initial FTP handshaking.
• Screen dumps: FTP application
• Download: raw data and nlv_keys files

Example 4: Visualization of Remote Data

• Description: This is an example of how NetLogger was used to tune a visualization application (Visapult) reading remote data from a DPSS. Before adding NetLogger, the application sequentially did IO, followed by computation. After seeing these results, it became clear that overlapping IO with computation would help a lot.
• Screen dumps: Visualization of Remote Data

Example 5: Network Monitoring (NTAF)

• Description: Example of using NetLogger to correlate the results of several network tests.
• Screen dumps: Network Monitoring (NTAF)
• Download: raw data and nlv_keys files

Example 6: Web100 Monitoring (iperf)

• Description: Example of how NetLogger can be used to analyze the results of iperf running on a web100 Linux kernel
• Screen dumps: Web100 Monitoring (iperf)
• Download: raw data and nlv_keys files

Additional examples

More raw data and examples may be available here.