1. Brian L. Tierney, Dan Gunter BLTierney@lbl.gov, DKGunter@.lbl.gov
NetLogger Summarizer
and the nlioperf tool
Brian L. Tierney, Dan Gunter
Lawrence Berkeley National Laboratory
Center for Enabling Distributed Petascale Science

2. NetLogger Toolkit
We have developed the NetLogger Toolkit (short for Networked Application Logger), which includes:
tools to make it easy for distributed applications to log interesting events at every critical point
NetLogger client library (C, Java, Perl, Python)
tools for host and network monitoring
event visualization tools that allow one to correlate application events with host/network events
NetLogger event archive and retrieval tools (new)
NetLogger combines network, host, and application-level monitoring to provide a complete view of the entire system.
Open Source, available at

3. NetLogger Analysis: Key Concepts
NetLogger visualization methodology is based on time correlated and object correlated events.
In order to associate a group of events into a “lifeline”, you must assign an “Event ID” to each NetLogger event
Sample Event ID: file name, block ID, frame ID, etc.

4. Time-based summarization
Imagine you want detailed instrumentation of a simple
loop that reads data, processes it, then writes out some result.
DO for i=1, N
log(“read.start”, ...)
read_data()
log(“read.end”, ...)
process_data()
log(“write.start”, ...)
write_data()
log(“write.end”, ...)
DONE

5. Time-based summarization
Reporting only a periodic summary (mean, sd) of times and values between “start” and “end” events (of a given type and ID).
.. to here
Go from here..
Orders of magnitude data reduction with, for many purposes, no loss in explanatory power.
Since the original instrumentation is still there, you can “turn on” and off the full detail in a running program.

6. Sample Use: GridFTP Bottleneck Detector
GridFTP today
By default only logs single throughput number
GridFTP throughput might be limited by
Sending/receiving disk
NFS/AFS mounted partition?
network
currently no way to tell
Experimental GridFTP enhancement
Use NetLogger summarization library to monitor all I/O streams

7. nlioperf
Started out as a test tool for the NetLogger summarization library
Actually quite useful test tool
Supports
multiple TCP streams
file input/output
TCP buffer tuning
bottleneck detection
multiple levels of logging
full, interval summary, final summary only

8. nlioperf: network vs disk performance

9. Bottleneck Detection: WAN Transfer

10. Ideas
Add NetLogger summarizer to iperf?
Add disk testing to iperf

11. More Information NetLogger 4.0beta just released
includes new summarization Library: or