From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
From: Peter Schay <pschay@pobox.com>
Message-ID: <3AF8C3CC.88BBAE0C@pobox.com>
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Subject: [9fans] env walk optimization
Date: Wed,  9 May 2001 08:30:01 +0000
Topicbox-Message-UUID: 9bff240a-eac9-11e9-9e20-41e7f4b1d025

Hello,

Here's more on the performance subject; I hope the
following optimization is useful and not too inelegant.

The algorithm for walking in #e seems to be O(n*n).
I think it's pretty easy to make it O(n).

For example, on my system the following script takes no
time with 42 environment variables takes 4 seconds with
441 vars:

term% time /fd/0 <<.
#!/bin/rc
rfork e
eval X^(`{seq 1})^('=1')
echo nvars `{ls /env | wc -l}