Thanks, So in this case reading some of your past responses (and your source knowledge), we do not have to worry about threaded mod_jk misbehaving in a prefork apache - on linux and solaris that is :-)
Rgds - Fred Rainer Jung-3 wrote: > > Hi Fred, > > mostly yes, but you could write modules, that break this assumption. An > indication is mod_cgi, which exists as mod_cgi and mod_cgid. Another > hint into this direction is, that httpd doesn't provide a clean way of > exchanging MPMs after compilation. > > In general it is better to compile the module against the MPM you want > to use unless you know the code of the module good enough to judge about > its MPM independancy. > > Regards, > > Rainer > > fredk2 wrote: >> Many thanks for your reply. >> Is it always implied that if an apache module is deemed 'thread safe' it >> also implies that it will work in "prefork" environment maybe at the cost >> of >> raw performance ? >> >> Thanks again - Fred >> >> >> Rainer Jung-3 wrote: >>> fredk2 wrote: >>>> Hi, >>>> >>>> The documentation for mod_jk (eg. version 1.2.25) about >>>> --enable-prefork >>>> says: >>>> >>>> "In case you build mod_jk for a multi-threaded Apache httpd 2.0/2.2 MPM >>>> (Multi-Processing Module), some areas of mod_jk code need to be >>>> synchronized >>>> to make it thread-safe. Because configure can not easily detect, >>>> whether >>>> your are using a multi-threaded MPM, mod_jk by default is always build >>>> thread-safe for Apache httpd 2.0/2.2. If you are sure, that your MPM is >>>> not >>>> multi-threaded, you can use "--enable-prefork" to force the removal of >>>> the >>>> synchronization code (thus increasing performance a bit). For instance, >>>> the >>>> prefork MPM is not multi-threaded. For Apache httpd 1.3 this flag will >>>> be >>>> set automatically." >>>> >>>> >>>> If you specify apxs, doesn't it require a config_vars.mk which has a >>>> value >>>> pair MPM_NAME = prefork and thus configure could know that prefork was >>>> used? >>>> Alternatively assuming that apxs is in the same directory then 'httpd >>>> -V' >>>> could tell that >>>> "Server MPM: Prefork" >>> You are right: "apxs -q MPM_NAME" would do the trick. I didn't find that >>> one, thanks. On the other hand, we would still need to manage a list of >>> MPMs (which MPM on which platform is single-threaded) and there is some >>> danger, that people have more than one mpm installed (like on many linux >>> distros) and compile against prefork, later use against worker. All in >>> all I'm still in favor of building thread safe by default and only when >>> explicitely requested removing the thread synchronization. >>> >>>> The question I have: if the Apache httpd v2.2 is prefork and the mod_jk >>>> is >>>> compiled "default threaded", are there any potential instabilities? (on >>>> Solaris and Linux) >>> No, not that we aware of any. On both platforms, the default was >>> building thread safe for a long time. We use pthread mutexes and no >>> problems have been reported with those. >>> >>>> Many thanks - Fred >>> Regards, >>> >>> Rainer > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > -- View this message in context: http://www.nabble.com/mod_jk---enable-prefork-tf4417291.html#a12628071 Sent from the Tomcat - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
