Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!emory!gatech!prism!scott From: scott@prism.gatech.EDU (Scott Holt) Newsgroups: comp.unix.aix Subject: Re: Does SIGXCPU work under AIX 3.1? Message-ID: <22867@hydra.gatech.EDU> Date: 26 Feb 91 19:06:52 GMT References: <6893@mace.cc.purdue.edu> Organization: Georgia Institute of Technology Lines: 40 In article <6893@mace.cc.purdue.edu> abe@mace.cc.purdue.edu (Vic Abell) writes: >The attached test program works under BSD 4.3-Tahoe, Ultrix 2.2, SunOS >4.0.3, NeXTOS 1.0 and DYNIX 3.0.12. It doesn't work under AIX 3.1 >(3003). What else do I need do to limit CPU time? > >Csh's "limit cputime nnn" command doesn't seem to work, either. > >Vic Abell In short - no. SIGXCPU does not work. Despite documentation to the contrary (see info pages for set/getrlimit), A SIGXCPU is not sent to a process upon reaching its soft CPU time limit. Nothing is sent at all - there is no CPU time limit under AIX 3. I reported this problem to IBM and their response was that it was a documentation error. They refered me to the info entry for the Limits file - which states that the CPU time limit in the file is not used. Their fix - change the documentation to setrlimit. In all fairness to the software defects group - they were actually quite helpfull...but what can they do other than collect the details and refer the problem to the developers. They suggested the route I am going to take, put in a request for a design change through our local reps. Perhaps you should do the same. For us, the ability to have a CPU time limit is crucial - we plan to implement a processor farm of sorts managed by a batch management system such as NQS. CPU time limits (as well as memory limits and others that AIX does support) are vitally important to such a system - especially when batch queue priorities and job scheduling are to be based on resource demands. If we can't have a reasonable method to enforce all resource limits, then we cannot use the machine for this project. - Scott -- This is my signature. There are many like it, but this one is mine. Scott Holt Internet: scott@prism.gatech.edu Georgia Tech UUCP: ..!gatech!prism!scott Office of Information Technology, Technical Services Brought to you by Super Global Mega Corp .com