Sun Studio 12: C User's Guide

B.2.95 -xjobs=n

(SPARC) Specify the -xjobs option to set how many processes the compiler creates to complete its work. This option can reduce the build time on a multi-cpu machine. Currently, -xjobs works only with the -xipo option. When you specify -xjobs=n, the interprocedural optimizer uses n as the maximum number of code generator instances it can invoke to compile different files.

Generally, a safe value for n is 1.5 multiplied by the number of available processors. Using a value that is many times the number of available processors can degrade performance because of context switching overheads among spawned jobs. Also, using a very high number can exhaust the limits of system resources such as swap space.

You must always specify -xjobs with a value. Otherwise an error diagnostic is issued and compilation aborts.

Multiple instances of -xjobs on the command line override each other until the right-most instance is reached.

The following example compiles more quickly on a system with two processors than the same command without the -xjobs option.

 example% cc -xipo -xO4 -xjobs=3 t1.c t2.c t3.c

It is illegal to specify -xipo_archive without a flag.