click: proc_dir missing from cvs repository; scheduled events in click; new serial link emulator element

[Eric Freudenthal]

Click-masters,
I checked out the current version of click from the cvs repository and found
a reference in linuxmodule/Makefile.in to proc_dir.o, but no relevant source
file.   Proc_dir.o is not required by the version of click we checked out in
March.  I can not build the current version without it.

Also, we have added a scheduled event mechanism to the version of click
we're running (March 2002).  These events are implemented as callbacks
scheduled to be executed a particular time.  These events are stored in a
min-heap ordered by event schedule that is consulted each time the click
task queue is checked.

We use these scheduled events efficiently implement a new element
"SerialLink" that emulates a fixed-length queue feeding a fixed bandwidth
transmission line with fixed end-to-end latency.  These elements require no
conventional click threads.  We are seeing good performance for systems
containing hundreds of these elements.   I suspect that many other click
elements can be rewritten using this mechanism.
Would you like to consider including these modifications into the click
source tree?

Eric & Tao

Eric Freudenthal  // Courant Institute // New York University
719 Broadway, Room 712 // New York, NY // 10003
office: 212-998-3345 // cell: 917-279-6208