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

[Eric Freudenthal]

Well, we didn't notice the existing timer facilities, but we think that ours
are better for our purposes:

1. our scheduled events take a function and two args, we use one arg to
identify the object and the other to identify the packet to send.
2. we expect to have many events scheduled, and a min_heap has faster random
insertion time than than a linked list
3. we need to schedule events with finer granularity than 1ms; our scheduler
attempts 1us granularity (well, that's too fine), and checks the timer
between running threads.

The click latency & bandwidth shapers are natural candidates for conversion
to scheduled events.  I assume that most of the threaded elements are good
candidates for conversion.

We'll pick up your code & build a patch file in the next couple of days.

Eric

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

-----Original Message-----
From: Eddie Kohler [mailto:kohler at icir.org]
Sent: Thursday, May 02, 2002 4:21 PM
To: Eric Freudenthal
Cc: Click Moil List; Tao Zhao
Subject: Re: click: proc_dir missing from cvs repository; scheduled events
in click; new serial link emulator element

Hi Eric and Tao,

Sorry about proc_dir.o. Some half-done changes in a local sandbox got into
the CVS repository; they've been reverted.

> 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.

Neat! We'd love to see the patch. Can you send it along to the list??
Include your SerialLink element, too. And, if it's not too hard, mention an
existing element that you think should use your mechanism.
How different are scheduled events from Click's current Timers?

Eddie