Add flag to skip execution of workload #15
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Currently the `-c` option does not (reliably) support execution of pinpoint without a workload. It is still useful to get data from pinpoint without a workload - especially if just getting the raw data of a powermeter is the goal.
| sampler.start(std::max(-settings::before, std::chrono::milliseconds(0))); | ||
| waitpid(workload, NULL, 0); | ||
| std::promise<void>().get_future().wait(); // waits forever |
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This is not optimal in my opinion, but I think waiting forever here is needed due to the program design.
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Alternatively, we could use the syscall pause(): https://man7.org/linux/man-pages/man2/pause.2.html it seems - if we can rely on that syscall existing.
| @@ -133,7 +139,7 @@ void readProgArgs(int argc, char *argv[]) | |||
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| if (!(optind < argc)) { | |||
| if (!(optind < argc) || no_workload_flag) { | |||
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I hope that this doesn't cause any buggy behavior.
| exit(1); | ||
| } | ||
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| if (!workload_and_args && !(no_workload_flag && continuous_print_flag)) { |
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I think this error message needs to be improved. I needed quite some time to understand what this means. This should hint at the -h option at least.
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My approach to this was calling |
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Yes, that’s an option probably. But it also feels hacky. I‘d prefer not to fork a process if it’s not needed. As context: We are using our fork of pinpoint to get data from power meters in our application (https://github.com/nsg-ethz/autopower/blob/956049c2fef02fe1763eb596110164ac253092c1/client/client.cc#L225) and write the measurements into a database. There are multiple small changes (Build for Raspberry Pi, printing measurement samples to stdout reverting parts of 84c59ab) with this being one of the earliest ones. Should I open an issue on those changes? |
Currently the
-coption does not (reliably) support execution of pinpoint without a workload. It is still useful to get data from pinpoint without a workload - especially if just getting the raw data of a power-meter is the goal like in a project I am working on. This PR introduces a-nflag to skip the need of a workload.pinpoint -c -e CPU -was initially used to execute without a workload. However, I think this is a bug and not really a supported feature. Moreover, this command does not reliably run forever: Sometimes it terminates immediately which I think is due to a race condition related to not having a valid workload.Alternatively, the
-ccommand could be updated to have different semantics if no workload is given.This change needs an entry in the README file, but #13 should probably be merged first.