Here is DataComm-1 at a glance:

The DataComm-1 workload is close to PolyMix-1 used during the first Web cache cache-off. Please read the description of PolyMix-1 before using DataComm-1; we do not duplicate common information.

The major difference between PolyMix-1 and DataComm-1 is the presence of persistent connections in the latter. The model for persistent connections is simple, but allows us to capture the main characteristics of HTTP/1.1 connections -- the total number of requests on a single persistent connection. Significantly improving the model any further would require support of client "sessions" and HTML content.

DataComm-1 also has longer, fewer tests compared to PolyMix-1.

2.1 Client configuration

A handy file with raw, unformatted command line options is available. Here is a more readable version:

polyclt \
	--verb_lvl 4 \
	--ports 1024:30000 \
	--proxy $Proxy \
	--origin $Server\ 
	--launch_win 1min \
	--rep_cachable 80p \
	--pconn_use_lmt zipf:64 \
	--nagle off \
	--robots 1 \
	--req_rate $RR/sec \
	--dhr 55p \
	--pop_model unif \
	--tmp_loc none \
	--cool_phase 1min \
	--goal -1:4hr:0.30
	--log_size 15MB

Note that we disable the Nagle algorithm (i.e., TCP acknowledgements are not delayed) to utilize the full potential of persistent connections. See the --nagle option for details.

A handy file with raw, unformatted command line options is available. Here is a more readable version:

polysrv \
	--port 80 \
	--verb_lvl 4 \
	--idle_tout 135sec \
	--pconn_use_lmt zipf:16 \
	--nagle off \
	--xact_think norm:3s,1.5s \
	--obj_bday const:-1year \
	--obj_with_lmt 100p \
	--obj_life_cycle const:2year \
	--obj_expire 100p=lmt+const:1 \
	--goal 4.1hr
	--log_size 15MB

Object Life Cycle options were not used for PolyMix-1. However, the options emulate PolyMix-1 workload to the extent possible:

• objects were last modified (born) a year ago
• objects have a two year life cycle
• the expiration time is set to match next modification time
• both modification and expiration times are reported for all cachable objects

The differences from the PolyMix-1 workload are:

• presence of persistent connections
• modification and expiration times are now reported for uncachable objects
• Date: response header field is included in every reply
• If-Modified-Since: requests (if any) are handled correctly
• longer experiments (4 hours versus 1 hour in PolyMix-1)

DataComm-1 has only one parameter, namely request rate RR. The rate is specified using the --req_rate command line option. At most two request rates will be used for each cache under test.

3. More Information

See the PolyMix-1 workload for useful hints and related pointers.