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Re: PCL benchmark
- To: Chris Burdorf <email@example.com>
- Subject: Re: PCL benchmark
- From: Gregor.pa@Xerox.COM
- Date: Wed, 19 Oct 88 11:02 PDT
- Cc: Stan Lanning <Lanning.pa@Xerox.COM>, Warren Harris <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org, Douglas Rand <email@example.com>, Rob Pettengill <rcp@sw.MCC.COM>, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, Chris@zaphod.prime.com, CommonLoops.PA@Xerox.COM, email@example.com, firstname.lastname@example.org, Bruce_Florman <email@example.com>
- Fcc: BD:>Gregor>mail>outgoing-mail-4.text.newest
- In-reply-to: <8810190147.AA12717@rand.org>
- Line-fold: no
Date: Tue, 18 Oct 88 18:46:56 PDT
From: Chris Burdorf <firstname.lastname@example.org>
I got rid of the formats and compiled with safety set to 0 and
speed at 3. I got the following times:
Gathering these times into one table we get:
20 cars 50 cars
ERNIE 1.000 2.686
PCL in AKCL 8.483 (x8) 26.300 (x10)
(speed 3, safety 0)
PCL in Allegro 2.020 (x2) 6.340 (x2.4)
(default compiler settings)
In these numbers, the PCL version of your program takes from 202% to
979% the time of the Ernie version.
Judging from these numbers, I would say that you should start writing
the rest of your code in CLOS. If the program you sent is an accurate
measure of what your programs really do, CLOS is going to do better for
you than Ernie.
Why do I say this:
- You claim that Ernie is finely tuned for performance. I
believe you. I claim that PCL is not operating anywhere
near its "theoretical" performance. Believe me.
- The best compilation you were able to give PCL in Allegro
was with default compiler settings. I am not sure, but I
think this has a significant negative effect. I will look
into this. I would also be interested in knowing why you
couldn't compiler it with speed 3 and safety 0, this is a
bug which should be fixed.
- From looking at your program, I believe it depends more
than anything else on the performance of reader generic
functions (those generic functions which have automatically
defined reader methods on them). Those will go considerably
faster in more tuned versions of PCL. In your Franz version,
they will probably be 2 - 3 times faster. In your KCL version
they may be as much as 7 - 8 times faster.
- The next most critical number for your program is generic
function call overhead. In more tuned ports of PCL this
will improve the same way that reader generic functions
will (2 - 3 times in Allegro, 7 - 8 times in KCL).
I can't tell you much about ERNIE, because it is funded by DOD
and I don't want to get tried for treason. It's basically a
reimplemtation of FLAVORS. It has practically everything Flavors
has, but it was designed especially to be fast.
This does and doesn't make sense to me.
Does: The Ernie performance numbers don't look all that
good, they seem to be what one would expect from
Doesn't: If I were designing something with efficiency as my
single I wouldn't start from Flavors. If efficiency
were not my my single goal, I would start with CLOS.
CLOS has the go good ideas from Flavors (and other
languages as well) and has been carefully designed
to allow efficient implementation.
Another point is that CLOS, with its metaobject protocol, can allow more
efficient user controlled, "staticizing" or "block compilation".
My main reason for sending out this comparison
of ERNIE and PCL was not to try and convert people to ERNIE, but to
try to stir a dialog on efficiency. Hopefully PCL will be fast for
all of us: rich or poor.
Yes, this is an important dialog. As for your cost concern, I believe
PCL will run well in KCL as well as in more expensive lisps.