From: "Robert Kindred" <RKindred@SwRI.edu>
To: "Stephen Croall" <scroall@tibco.com>,
"Evstiounin, Mikhail" <Mikhail.Evstiounin@ca.com>,
<pthreads-win32@sources.redhat.com>
Subject: RE: Good Algorithm for "Multiple Readers"/"Multiple Writers"
Date: Thu, 08 Dec 2005 14:53:00 -0000 [thread overview]
Message-ID: <IIEJIMCOHAKGODCMHFEOGENHCCAA.RKindred@SwRI.edu> (raw)
In-Reply-To: <D8495C6C606E0C47AF2720713E1B7A620116556D@NA-PA-VBE01.na.tibco.com>
Multiple writers doesn't make any sense at all to me, unless you mean a
message queue. I copied a good algorithm for this out of the POSA2 book
(Pattern Oriented Software Architecture Volume 2, Patterns for Concurrent
and Networked Objects).
Robert Kindred
> -----Original Message-----
> From: pthreads-win32-owner@sourceware.org
> [mailto:pthreads-win32-owner@sourceware.org]On Behalf Of Stephen Croall
> Sent: Thursday, December 08, 2005 8:08 AM
> To: Evstiounin, Mikhail; pthreads-win32@sources.redhat.com
> Subject: RE: Good Algorithm for "Multiple Readers"/"Multiple Writers"
>
>
>
> We already use read/write locks in places but for greater parallelism
> multiple reader and multiple writer locks would be better.
>
> The current read/write lock implementation in POSIX doesn't support
> multiple writers. Only one writer thread can process at a time - as I
> would expect.
>
> I'm after a good model for writing a "many readers"/"many writers" lock
> implementation, which is portable from Windows to UNIX.
>
> Steve.
>
> -----Original Message-----
> From: Evstiounin, Mikhail [mailto:Mikhail.Evstiounin@ca.com]
> Sent: 08 December 2005 14:02
> To: Stephen Croall; pthreads-win32@sources.redhat.com
> Subject: RE: Good Algorithm for "Multiple Readers"/"Multiple Writers"
>
> I did not quite get it. The difference between reader and writer is that
> reader locks out writer and lets other readers continue without waiting
> while writer acquire an exclusive lock. Multiple writers will have
> serialized access to a resource in any case. So, there no difference
> from this point of view between "one writer -- many readers" and "many
> writers -- many readers". So, if you are going to use FIFO (or you don't
> care -- I made an assumption that all requests for resource locking is
> based on FIFO which is not true, generally speaking) in terms of how to
> process request queue then posix approach is enough.
>
> -----Original Message-----
> From: pthreads-win32-owner@sourceware.org
> [mailto:pthreads-win32-owner@sourceware.org] On Behalf Of Stephen Croall
> Sent: Thursday, December 08, 2005 4:57 AM
> To: pthreads-win32@sources.redhat.com
> Subject: RE: Good Algorithm for "Multiple Readers"/"Multiple Writers"
>
>
> Thanks, but the POSIX read/write interface supports a single writer vs.
> multiple readers. I'm after multiple writers & readers i.e. multiple
> threads can perform writing but readers must wait and vice versa.
>
> Steve.
>
> -----Original Message-----
> From: Rustam T. Usmanov [mailto:rustam@unilib.neva.ru]
> Sent: 08 December 2005 09:54
> To: Stephen Croall
> Subject: Re: Good Algorithm for "Multiple Readers"/"Multiple Writers"
>
> On Thu, 8 Dec 2005, Stephen Croall wrote:
>
> > Is anyone aware of whether POSIX implements this type of lock?
>
> pthread_rwlock ? See
> http://www.opengroup.org/onlinepubs/009695399/functions/pthread_rwlock_i
> nit.html
>
> --
> Rustam Usmanov, systems engineer
> Institute of Consortia Library Information Systems,
> St.Petersburg State Polytechnic University
> Address: 29, Politekhnitcheskaya str., St.Petersburg, 195251, Russia
> Tel/fax: +7 812 552 7654 <URL:http://www.unilib.neva.ru/olsc/>
>
>
next prev parent reply other threads:[~2005-12-08 14:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-08 14:09 Stephen Croall
2005-12-08 14:53 ` Robert Kindred [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-12-08 16:35 Stephen Croall
2005-12-08 15:47 Evstiounin, Mikhail
2005-12-08 15:16 Stephen Croall
2005-12-08 15:11 Stephen Croall
2005-12-08 15:09 Stephen Croall
2005-12-08 15:06 Stephen Croall
2005-12-08 15:06 Evstiounin, Mikhail
2005-12-08 15:02 Evstiounin, Mikhail
2005-12-08 15:01 Stephen Croall
2005-12-08 15:00 Evstiounin, Mikhail
2005-12-08 14:49 Stephen Croall
2005-12-08 14:02 Evstiounin, Mikhail
2005-12-08 9:57 Stephen Croall
2005-12-08 9:09 Stephen Croall
2005-12-08 14:46 ` Robert Kindred
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=IIEJIMCOHAKGODCMHFEOGENHCCAA.RKindred@SwRI.edu \
--to=rkindred@swri.edu \
--cc=Mikhail.Evstiounin@ca.com \
--cc=pthreads-win32@sources.redhat.com \
--cc=scroall@tibco.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).