On Fri, Sep 05, 2025 at 01:45:31AM +0200, Marc Gonzalez wrote: > Then I run this script as root: > #!/bin/bash > > CMD="taskset -c 1 ./a.out" > if [ "$1" = "fifo" ]; then CMD="chrt -f 99 $CMD"; fi > > for I in $(seq 1 30); do > T0=$(date "+%s.%N") > $CMD > T1=$(date "+%s.%N") > echo "$T1-$T0" | bc -l > done This set setup is forking processes in order to get timestamps. This gives you uncontrollable variance in the measurement. Use clock_gettime inside your test program. Also you might want to reduce the prio to 98.
