Performance: compile options

Antti Kantee edited this page Mar 17, 2014 · 1 revision
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A rump kernel is designed to run anywhere with sensible defaults. This page documents compile options that improve runtime performance.

remove assertions

Run with either -V RUMP_DIAGNOSTIC=no or -r (the latter also removes -g, which will result in smaller binaries). This will eliminate invariant assertions from the rump kernel, and can improve performance about 5%.

static linking

Dynamic linking is slower than static linking due to added indirections in resolving symbol addresses at runtime. One option is to compile the application binary the completely statically (rumpmake LDSTATIC=-static). Another option is to include only static components in your rump kernel installation by running with -V MKPIC=no.

locking scheme

If you are planning to run rump kernels with exactly 1 virtual core configured (RUMP_NCPU=1), run with -V RUMP_LOCKS_UP=yes. This will optimize away most memory bus locks.