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Parallelhashlist was updated to version 1.41 ...
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aminer
May 30, 2012, 7:34:51 PM5/30/12
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Hello all,
I have updated parallelhashlist to version 1.41..
I have modified parallelhashlist to use 128 locks, but you
have to use a hashsize in power of 2 and greater to 1000,
how do you pass a hashsize in power of 2 to the constructor?
by using shl operation like this
trait:=TCaseinsensitiveTraits.create;;
hash1:=TParallelHashList.create(trait,1 shl 25);
Why do you have to use a power of 2 ?
Please read this:
Power-of-Two Hash Table Size
"Any data structures 101 book will say choose a prime for the
number of buckets, so that the bucket's index can easily be computed
by h(k) = k mod m, where k is the key value and m is the bucket size.
While this approach is straight-forward, there are a number of issues
with it, including slow modulo performance. ConcurrentHashMap instead
uses a power-of-two rule"
http://work.tinou.com/2008/09/performance-optimization-in-concurrenthashmap.html
I am using modulo functions inside parallelhashlist, and using a number of
locks
in power of 2, so you have to use hashsize in power of 2 , this will make
the
modulo function of the delphi and freepascal compilers 10X faster.
You can download parallelhashlist version 1.41 from:
http://pages.videotron.com/aminer/
Thank you.
Amine Moulay Ramdane.
aminer
May 30, 2012, 7:38:56 PM5/30/12
to
I wrote:
>I have modified parallelhashlist to use 128 locks
Thank you.
Amine Moulay Ramdane.
news:jq67al$4i9$1...@dont-email.me...
aminer
May 30, 2012, 7:46:38 PM5/30/12
to
I wrote:
>I am using modulo functions inside parallelhashlist, and using a number of
>locks in power of 2, so you have to use hashsize in power of 2 , this will
>make the modulo function of the delphi and freepascal compilers 10X faster.
I mean that the modulo function that i am using a lot inside
>I am using modulo functions inside parallelhashlist, and using a number of
>locks in power of 2, so you have to use hashsize in power of 2 , this will
>make the modulo function of the delphi and freepascal compilers 10X faster.
parallelhashlist
is 10X faster when the hashsize is power of 2 than when it's not power of 2.
Thank you.
Amine Moulay Ramdane.
aminer
Jun 2, 2012, 7:38:29 PM6/2/12
to
Hello,
I have done some scalability tests on parallelhashlist 1.41
on an Intel Core 2 Quad Q6600..
Using 4 threads on 4 cores using the find() method i had a perfect scale of
4X .
Using 4 threads on 4 cores using the Add() method i scaled 3.4X
Regards,
Amine Moulay Ramdane.
aminer
Jun 2, 2012, 7:40:17 PM6/2/12
to
Hello,
I have done some scalability tests on parallelhashlist 1.41
on an Intel Core 2 Quad Q6600..
Using 4 threads on 4 cores using the find() method i had a perfect scaling
I have done some scalability tests on parallelhashlist 1.41
on an Intel Core 2 Quad Q6600..
of 4X .
Using 4 threads on 4 cores using the Add() method i had a scaling of 3.4X
Regards,
Amine Moulay Ramdane.
aminer
Jun 2, 2012, 7:52:52 PM6/2/12
to
Hello,
I have done those tests to show some numbers...
But the scalability of parallelhashlist does depend on the data keys
that are presented to parallelhashlist, when the data keys are hashed
and are very well distributed across the segments, in fact you can
get a perfect 4X scaling both on reads and writes.
Thank you.
Amine Moulay Ramdane.
I have done those tests to show some numbers...
But the scalability of parallelhashlist does depend on the data keys
that are presented to parallelhashlist, when the data keys are hashed
and are very well distributed across the segments, in fact you can
get a perfect 4X scaling both on reads and writes.
Thank you.
Amine Moulay Ramdane.
"aminer" <ami...@videotron.ca> wrote in message
news:jqe4lc$sf9$1...@dont-email.me...
aminer
Jun 2, 2012, 7:56:36 PM6/2/12
to
I write:
>But the scalability of parallelhashlist does depend on the data keys that
>are presented to parallelhashlist, when the data keys are hashed and are
>very well distributed across the segments, in fact you can get a perfect 4X
>scaling both on reads and writes.
I mean a perfect scaling on 4 cores...
>But the scalability of parallelhashlist does depend on the data keys that
>are presented to parallelhashlist, when the data keys are hashed and are
>very well distributed across the segments, in fact you can get a perfect 4X
>scaling both on reads and writes.
Regards,
news:jqe5ga$ts$1...@dont-email.me...
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