Re: [perl #39063] [RESOLVED] [TODO] ResizableBooleanArray uses 64 bytes per bit of information

[Joshua Isom]

On Apr 16, 2007, at 8:46 AM, Andy Dougherty wrote:

On Sun, 15 Apr 2007, Allison Randal via RT wrote:

According to our records, your request regarding
  "[TODO] ResizableBooleanArray uses 64 bytes per bit of information"
has been resolved.



For other topics, please create a new ticket.

If you have any further questions or concerns, please respond to this message.

<URL: http://rt.perl.org/rt3/Ticket/Display.html?id=39063 >

Are you *sure* it's been fixed?  My test involved running a simple
program something like this

    .sub _main
        .local pmc pmc1
        pmc1 = new ResizableBooleanArray
        pmc1[1000] = 1
    .end

and incrementing the '1000'.  I found that for every element I added,

with -DDETAIL_MEMORY_DEBUG.)

Hence if I want to store 1,000 bits, parrot will call malloc() to
allocate 64,000 bytes.  That's why I said it "uses 64 bytes per bit of
information".

I apologize in advance if I have misunderstood the correct way to use
ResizableBooleanArray or what the number '1000' means in the above
example.

--
    Andy Dougherty              [EMAIL PROTECTED]

parrot allocated 64 extra bytes. (I monitored parrot's calls to malloc()

.sub _main
    .local pmc pmc1
    pmc1 = new .ResizableBooleanArray
    pmc1 = 100000
    $S0 = freeze pmc1
    $I0 = length $S0
    $S0 = $I0
    say $S0
    pmc1[1000000] = 1
    $S0 = freeze pmc1
    $I0 = length $S0
    $S0 = $I0
    say $S0
.end

Well using this script I seem to improve the results greatly... Using freeze is ugly and not best but the only way I could think of the really get the size of the pmc(especially since a pmc could compress it's data). I get 6400136 and 64000136 before, and 100080 and 1000080 now. But before applying this patch(which passes it's tests, and one unexpectedly), I'd probably recommend improving the testing suite.

rba.patch
Description: Binary data