Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.programming.threads > #879

Re: Parallelhashlist was updated to version 1.31 ...

Cross-posted to 2 groups.

Show all headers | View raw

Hello

You can use the parallel Iterate() method of parallelhashlist
when also you want to do a sort by keys, but don't forget
to use my other parallelsort library to sort in parallel your array
that you have to fill from inside the the TIterateFunc callback..

You can download my parallelsort library from:

http://pages.videotron.com/aminer/


Amine Moulay Ramdane.


"aminer" <aminer@videotron.ca> wrote in message 
news:jp6ji4$s0t$1@dont-email.me...
>
> Hello,
>
>
> In my previous version of ParallelHashList even if i have used
> lock striping , synchronizing access to the counter that computes
> the number of entries in the hashtable was reintroducing the scalability
> problem of exclusive locking, this counter was  called a hot field because
> every mutative operation needs to access it. In version 1.31, 
> parallelhashlist
> maintains an independant counter , that counts the number
> of entries , for each segment of the hashtable and it uses a lock
> for each counter and  this is better for scability.  also i have changed
> parallelhashlist to use only 100 lightweight  MREWs 
> (multiple-readers -exclusive-writer)
> this will lower the memory consumption  and  this allows multiple threads
> to write and read concurently. I am using lock striping with
> 100 lightweight MREWs (multiple-readers -exclusive-writer) and
> this allows up to 100 parallel writes, but this upper bound on
> parallel writes will not affect parallel reads, so this will give a good
> performance and a good scalability .
>
>
> Description:
>
> A parallel HashList with O(1) best case and O(log(n)) worst case
> access that uses lock striping and 100 lightweight MREWs
> (multiple-readers -exclusive-writer) , this allows multiple threads
> to write and read concurently. I am using lock striping with
> 100 lightweight MREWs (multiple-readers -exclusive-writer) and
> this allows up to 100 parallel writes, but this upper bound on
> parallel writes will not affect parallel reads, also parallelhashlist
> maintains an independant counter , that counts the number of
> entries , for each segment of the hashtable and uses a lock for
> each counter, this also for better scalability.
>
> You can download parallelhashlist version 1.31 from:
>
> http://pages.videotron.com/aminer/
>
>
> Language: FPC Pascal v2.2.0+ / Delphi 5+: http://www.freepascal.org/
>
> Operating Systems: Win , Linux and Mac (x86).
>
>
> and please take a look at the benchmarks here:
>
> http://pages.videotron.com/aminer/parallelhashlist/queue.htm
>
> Note: When i have done those benchmarks , there was not enough/much items
> organized as a self-balancing tree in the individual chains of the
> hashtable, so , almost all the items was found and inserted in O(1) , so
> the parallel part in the Amdahl equation was not much bigger compared
> to to the serial part. But you will notice in pratice that as soon as you 
> will have
> more items on the chains of the Hashtable, organized as self-balancing 
> tree,
> with a worst case log(n)  , the parallel part will become bigger in the 
> Amdahl
> equation and you will have better performance and scalability than the 
> numbers
> in the graph of the benchmarks
> ...
>
>
> Thank you.
>
> Amine Moulay Ramdane.
>
>
>
> 

Back to comp.programming.threads | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Parallelhashlist was updated to version 1.31 ... "aminer" <aminer@videotron.ca> - 2012-05-18 18:47 -0500
  Re: Parallelhashlist was updated to version 1.31 ... "aminer" <aminer@videotron.ca> - 2012-05-18 18:58 -0500
  Re: Parallelhashlist was updated to version 1.31 ... "aminer" <aminer@videotron.ca> - 2012-05-20 10:53 -0500

csiph-web