cc'd to jackit-devel list. This is a tricky problem. There was some concern about this previosuly. I wonder if its possbile to inspect the library map locations (ala "cat /proc/$$/maps", libelf maybe?) and selectivly munlock the ones that are known to be realtime unsafe (toolkits basicly). Its a bit of a gruesome hack, but it may help. - Steve On Thu, Jan 22, 2004 at 10:48:36 +0100, Robert Jonsson wrote: > On Thursday 22 January 2004 09.45, Christophe Vescovi wrote: > > Since there has been a lot of post concerning jack usage and > > optimisation recently it has remind me a problem I got that I never been > > able to understand. > > I have never been able to run jackstart with -R option when compiling > > jack with Sys V shm support. jackd -R as root work with SysV shm but if > > I want to use jackstart I have to use POSIX shm. > > The error message I am getting with SysV shm is the classical "cannot > > lock down memory for RT thread (Cannot allocate memory)". > > I am running a Mandrake 9.2 multimedia kernel (2.4.22, low latency, > > preemption and capability patches). > > Since most of jack users seem to use SysV shm I don't understand why I > > cannot (I am the only exception ....) > > > > Christophe > > Hi Christophe, > > I'm glad you brought it up, I have this problem too (actually with an Mdk9.2 > system but I don't think it's related) and have forgotten to report it back > here. > > I've done a fair bit of investigation in this area. The problem seems to be > that when locking the program tries to lock _all_ memory that the program > touches. > If you have DRI running in your X configuration (as I do) and utilize a QT > based program (as I do) there is a major problem. (It probably is similar > with other toolkits.) > I'm not sure of this but evidence suggest that QT maps the graphic memory > (available through DRI) into it's memory space. > What this means in reality is that with my 128mb graphic card QT apps occupy > 300mb of memory(!). With 512mb physical memory I sometimes manage to lock ONE > application, but never two. > > My "solution" has been to limit the amount of graphic-memory the x-server is > allowed to use by adding this line to the XF86Config-4 in the Section > "Device": > VideoRam 32768 > > thus limiting it to 32mb memory, which is quite enough for me. > Another solution is to remove DRI, but I use it so it can't be removed. > > --- > That there is a difference if you build with POSIX shm vs SysV shm I didn't > know. I guess there are still other problems with POSIX shm that keep you > from using that ? > > Regards, > Robert > >
