A simple cpulimit-like for user-interactive stuff.
Let's say your CPU is fast but you'd like to test a program as if it was running on way slower CPU.
You may consider cpulimit but it comes at a disadvantage: It steals
the time by big blocks. While this makes sense for batch jobs, it has
little use for testing UI interactivity or AV playback.
For this case, we need a tool that allows to specify how much time by what frequency we'd like to give that program time to run.
How? Just like cpulimit, send SIGSTOP and SIGCONT any when and then.
No cgroups, no driver hacks, no hardware clock setting, no VM, no sudo.
- Linux only.
- Does not support offspring processes.
- Not extremely precise, see below.
- Not correcting the delay of induced self-time.
Just compile the only file, like:
$ gcc main.c -o procclock
$ ./procclock PID TIME_US FREQ
With PID being the process ID of a running process, TIME_US the
time in microseconds that procclock grants to run between continuation
and suspension and FREQ the number of times per seconds this is
supposed to happen.
In case of TIME_US or FREQ being below the resolution of what
nanosleep actually is capable of, these values are set to
next-best level.
Use Ctrl + C to stop procclock and leave the process run at full speed again.
The Unlicense, please confer to the LICENSE file.