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0 pointsfrozenport9y ago0 comments

On Windows "std::cout" can take upwards of 3ms. I noticed this when writing high speed camera software that was supposed to hit my callback every 2ms. Instead it was limited by my print statement!

Does this emulator solve my problem?

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4 comments · 2 top-level

netheril969y ago· 1 in thread

Windows console is very slow (and terrible in many other ways). I think it is beyond salvageable. The only workarounds is probably write into a disk file or a pipe.

Zardoz849y ago

Try to use Cygwin + Mintty .

However, keeps being slower that any tty on any *nix. Sometimes fish autocomplete hangs for a few seconds when on the same machine running ubuntu fish autocomplete always is instantaneous. I don't know if it's related to something about the tty emulator or something weird on cygwin.

mrec9y ago· 1 in thread

3ms sounds pretty dire, if you weren't writing very much. Out of curiosity, was this with or without `std::ios::sync_with_stdio(false);` ?

I've found syncing makes a huge difference to IO perf in Windows, e.g. `_getc_nolock` is much faster than `getc`. (Assuming of course that you can get away with it.)

frozenportOP9y ago

That's what I thought, but then I measured.

These have little effect, also omitting std::endl has little effect. The effect is somewhat mitigated by buffering, so that if the time between subsequent st::couts is large, you won't see the runtime overhead.

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