arch/sim: add simulated time ratio support#18801
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xiaoxiang781216 merged 2 commits intoapache:masterfrom Apr 25, 2026
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arch/sim: add simulated time ratio support#18801xiaoxiang781216 merged 2 commits intoapache:masterfrom
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Add CONFIG_SIM_WALLTIME_RATIO Kconfig option and --sim-rt-ratio= command-line argument to control the ratio of simulated time to real time in percent. 100 means real-time (default), 200 means simulated time advances twice as fast, 50 means half speed. The implementation applies the ratio in host_gettime(), host_sleepuntil() and host_settimer() so both SIM_WALLTIME_SLEEP and SIM_WALLTIME_SIGNAL modes are supported. This is inspired by the --rt-ratio feature in Zephyr's native_sim board. Tested on sim:nsh with the following sleep test: $ echo -e "sleep 2\nexit" | time ./nuttx real 0m2.0xxs $ echo -e "sleep 2\nexit" | time ./nuttx --sim-rt-ratio=200 real 0m1.0xxs $ echo -e "sleep 2\nexit" | time ./nuttx --sim-rt-ratio=50 real 0m4.0xxs Signed-off-by: Lingao Meng <menglingao@xiaomi.com>
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dispatch_walltime() expects a delta in nanoseconds from now, but the previous code subtracted CLOCK_REALTIME from a CLOCK_MONOTONIC absolute timestamp, which have different epochs and produce a meaningless result. Fix by subtracting the current CLOCK_MONOTONIC absolute time to get the correct remaining duration. Signed-off-by: Lingao Meng <menglingao@xiaomi.com>
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Add CONFIG_SIM_WALLTIME_RATIO Kconfig option and --sim-rt-ratio=
command-line argument to control the ratio of simulated time to
real time in percent. 100 means real-time (default), 200 means
simulated time advances twice as fast, 50 means half speed.
The implementation applies the ratio in host_gettime(), host_sleepuntil() and host_settimer() so both SIM_WALLTIME_SLEEP and SIM_WALLTIME_SIGNAL modes are supported.
Tested on sim:nsh with the following sleep test: