From: "Patrick R. Michaud" <[EMAIL PROTECTED]>
Date: Mon, 31 Mar 2008 23:15:43 -0500
On Mon, Mar 31, 2008 at 11:33:42PM -0400, Bob Rogers wrote:
> Do you remember the discussion two years ago [1] about eliminating the
> user stack in favor of arrays? Chip made the following comment [2]:
>
> From: Chip Salzenberg <[EMAIL PROTECTED]>
> Subject: User stack: Worthwhile?
> Date: Mon, 27 Feb 2006 09:46:42 -0800
>
> Is there any other client of the user stack that can't be easily
> replaced by some kind of *Array? It'd be nice to lop off such a
> low-value feature.
>
> The response (including yours) was generally in favor of chucking this
> vestige of 1960's computer architecture, but nobody took up the mantle.
> What is the current thinking on this?
Unless user stack operations are somehow more efficient than
Resizable*Array PMCs, I don't see any reason for keeping them around.
Pm
To my great surprise, save and restore are more than 5x slower compared
to array push/pop, at least according to the simple benchmarks attached.
The save/restore version takes about 19s (user CPU) on my machine, but
the array push/pop version takes less than 3.6s. I haven't calibrated
the loops, nor have I tried types other than integer, but given the huge
difference for integers, I'm not sure I even need to bother.
================
From: "jerry gay" <[EMAIL PROTECTED]>
Date: Mon, 31 Mar 2008 20:43:12 -0700
my current thinking agrees with chip's and patrick's. the closer to
stackless we are, the better we handle threading. if you want to kill
it, i will not stand in your way.
~jerry
The stack is actually stored in the Parrot_Context (oddly enough), so
IIUC it shouldn't affect threading. True?
================
From: chromatic <[EMAIL PROTECTED]>
Date: Mon, 31 Mar 2008 20:45:14 -0700
If it's clean, I'm all for it.
-- c
I'm way too short of tuits right now, but I'll add a ticket when I get a
chance. (Anybody who wants to help could start by rewriting code that
uses anything in src/ops/stack.ops -- and TIA!)
-- Bob
.sub main :main
.local pmc stack
stack = new 'ResizableIntegerArray'
.local int max_depth
max_depth = 100
## Do this 100 000 times.
I2 = 100000
again:
## Push max_depth integers, and pop them off again.
I0 = max_depth
push_loop:
save I0
dec I0
if I0 > 0 goto push_loop
pop_loop:
restore I0
if I0 < max_depth goto pop_loop
dec I2
if I2 > 0 goto again
print "done.\n"
.end
.sub main :main
.local pmc stack
stack = new 'ResizableIntegerArray'
.local int max_depth
max_depth = 100
## Do this 100 000 times.
I2 = 100000
again:
## Push max_depth integers, and pop them off again.
I0 = max_depth
push_loop:
push stack, I0
dec I0
if I0 > 0 goto push_loop
pop_loop:
I0 = pop stack
if I0 < max_depth goto pop_loop
dec I2
if I2 > 0 goto again
print "done.\n"
.end
