Use clock_gettime instead of gettimeofday, it's more efficiency on low power system #1979
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Mullin
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Disregarding portability issues (I don't believe OSX has clock_gettime()), this is actually a good idea on Android; it prevents the clock jumping around if the system is set to update automatically from the network and the device switches between cell towers that aren't perfectly synchronized. |
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Yeah, i know. I just forgot to add a def for OSX. I'm a bit busy. I commit soon as possible :) |
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Please fix up the commit history. |
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Definitely agree about using clock_gettime and CLOCK_MONOTONIC being superior, but I really doubt this is any different in terms of efficiency. In fact, I would expect gettimeofday to be faster on x86_64 according to the VDSO implementation (gettimeofday is implemented as do_realtime + a division, while clock_gettime needs to also branch depending on the clock type). |
| struct timeval t; | ||
| (void)gettimeofday(&t, nullptr); | ||
| return ((u64)(t.tv_sec * 1000000 + t.tv_usec)); | ||
| return ((u64)(t.tv_sec * 1000 + t.tv_usec / 1000)); |
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Hmmm.. So just defined clockgettime for ARM devices and x86 and leave gettimeofday for x86-64 |
Mullin
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Don't, nobody cares about its efficiency anyway (I can't imagine a situation where it would be the bottleneck). CLOCK_MONOTONIC has clear advantages. |
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FYI, you can use http://shiftedbits.org/2008/10/01/mach_absolute_time-on-the-iphone/ (and you can pretty much ignore the timebase thing, it's always gonna be nanoseconds.) |
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@skidau history fixed. |
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@dolphin-emu-bot rebuild |
| @@ -237,7 +252,7 @@ double Timer::GetDoubleTime() | |||
| #ifdef _WIN32 | |||
| double ms = tp.millitm / 1000.0 / 1000.0; | |||
| #else | |||
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Benchmark on Armv7 : |
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I'd like to see those commits squashed, else LGTM |
…power system Add def for mac(They don't support clock_gettime) Fix my mistake Fix my mistake 2
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Squashed :) |
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@dolphin-emu-bot rebuild |
Use clock_gettime instead of gettimeofday, it's more efficiency on low power system
Use clock_gettime instead of gettimeofday, it's more efficiency on low power system