If Base is compiled with USE_POSIX_THREAD_PRIORITY_SCHEDULING = YES +in configure/CONFIG_SITE or related files, the Posix implementation of the +libCom osiSpawnDetachedProcess() routine will switch the child process +to use the normal SCHED_OTHER (non real-time) scheduler before executing the +named executable program. If it needs to use the real-time scheduler the new +program can request that for itself.
+ +On Posix systems, an IOC application's ability to meet timing deadlines is +often dependent on its ability to lock part or all of the process's virtual +address space into RAM, preventing that memory from being paged to the swap +area. This change will attempt to lock the process's virtual address space into +RAM if the process has the ability to run threads with different priorities. If +unsuccessful, it prints an message to stderr and continues.
-On POSIX systems, an IOC application's ability to meet timing deadlines is often -dependent on its ability to lock part or all of the process's virtual address space -into RAM, preventing that memory from being paged to the swap area. This change will -attempt to lock the process's virtual address space into RAM if the process has the -ability to run threads with different priorities. If unsuccessful, it prints an -message to stderr and continues.
-On Linux, one can grant a process the ability to run threads with different
-priorities by using the command ulimit -r unlimited. To use the FIFO
-scheduler for an IOC, use a command like this:
ulimit -r unlimited. To use the
+FIFO scheduler for an IOC, use a command like this:
- -chrt -f 1 softIoc -d test.db
On Linux, one can grant a process the ability to lock memory using the command
-ulimit -l unlimited. These limits can also be configured on a per
-user/per group basis by changing /etc/security/limits.conf or its equivalent.
In Linux, a child process created via fork inherits its parent's resource -limits. Thus, it is probably a good idea to start the caRepeater before -starting the IOC.
+ +On Linux, one can grant a process the ability to lock itself into memory
+using the command ulimit -l unlimited. These limits can also be
+configured on a per user/per group basis by changing /etc/security/limits.conf
+or its equivalent.
A child process created via fork() normally inherits its parent's resource +limits, so a child of a real-time soft-IOC will get its parent's real-time +priority and memlock limits. The memory locks themselves however are not +inherited by child processes.