On Fri, Oct 07, 2005 at 10:24:28AM -0400, Rutherdale, Will wrote: > Thanks, Tim and Jonathan. > > The motivator for the question is that I'm looking to recommend upgrades to > management in a month or two, e.g. for library versions (DBI, DBD, etc.), > Perl versions, and extra libraries to install. These upgrades would be > applied to a number of machines so they have to be planned. > > I'm not sure what you meant, Tim, when you referred to extensions. Do you > mean non-pure-Perl libraries that require compiling C code, such as DBI and > most DBDs?
Yes. > If so I can see the sense in the restriction, as usually the > library has to be compiled so as to be compatible with the Perl that will be > using it. > > I'm wondering if anyone has benchmarks comparing Perl with threads against > Perl without threads. If it's a 2% slowdown (for instance) it wouldn't be > such a big deal, but 50% would bother me. At least 10%, I've often seen 30% mentioned, and sometimes 100%+. As always, you should do your own benchmarks for your own tasks. Tim. > -Will > > BTW My personal take on email layout is that top-quoting is better 90% of > the time because people see up front what I have to say uncluttered and can > refer to the earlier discussion as needed. I use bottom quoting when I plan > to respond point-by-point several times. > > -----Original Message----- > From: Tim Bunce [mailto:[EMAIL PROTECTED] > Sent: Friday 07 October 2005 04:39 > To: Jonathan Leffler > Cc: Rutherdale, Will; List - DBI users > Subject: Re: Perl DBI and threads.pm > > > On Thu, Oct 06, 2005 at 07:42:14PM -0700, Jonathan Leffler wrote: > > On 10/6/05, Rutherdale, Will <[EMAIL PROTECTED]> wrote: > > > > > We have some Perl DBI scripts and have been running them on a Perl > > > compiled > > > with threading disabled. (I.e. perl -V gives ...usethreads=undef...). I > > > also have another environment where Perl is compiled with > > > usethreads=define > > > and have found the threading capabilities useful. (This is the Perl 5.8 > > > threads.pm <http://threads.pm> variety.) > > > > > > My question is this: if I were to upgrade the platform with the > threadless > > > Perl to a threaded Perl, would this risk reducing stability or > reliability > > > of the existing Perl DBI applications? > > > > > > These applications wouldn't be using multithreading, just switching to a > > > Perl with threading enabled. > > > > I don't have the hands on experience, so if someone with such experience > > contradicts me, you should probably take their advice over mine. > > > > My understanding is that a Perl with multi-threading where you do not use > > the multithreading should be as stable as a Perl without the > multithreading. > > However, there's a chance that some modules may not be so happy. OTOH, DBI > > shouldn't be one of those modules; it ensures single-tracking through it. > > OTOOH, if you aren't using the multi-threading, there still shouldn't be > any > > problem. > > I'd only add that a) the two builds aren't binary compatible so you > can't just copy extensions between them, and b) perl built with > multi-threading enabled is significantly slower. > > Tim. > > > - - - - - - - Appended by Scientific-Atlanta, Inc. - - - - - - - > This e-mail and any attachments may contain information which is > confidential, proprietary, privileged or otherwise protected by law. The > information is solely intended for the named addressee (or a person > responsible for delivering it to the addressee). If you are not the intended > recipient of this message, you are not authorized to read, print, retain, > copy or disseminate this message or any part of it. If you have received this > e-mail in error, please notify the sender immediately by return e-mail and > delete it from your computer. >
