4 ms·

This is why computers are slow.

secondcoming 6y ago
No. Just things written by web devs. (Shots fired)
saagarjha 6y ago
I was curious how slow this would be, and here is what JavaScriptCore made of this code: function clamp(n, min, max) { return [min, n, max].sort((a, b) => a - b)[1]; } for (var i = 0; i < 10000000; i++) { clamp(Math.random() | 0, Math.random() | 0, Math.random() | 0); } However, I was pretty disappointed when it seemed to be calling sort each time :( Perhaps I profiled it incorrectly? jsc's profiling data shows that it never hit FTL and nothing ever got inlined. The bytecode for DFG and Baseline is identical: Compilation clamp#CChm91-1-Baseline: arg0: predicting OtherObj arg1: predicting BoolInt32 arg2: predicting BoolInt32 arg3: predicting BoolInt32 [ 0] enter [ 1] get_scope loc4 [ 3] mov loc5, loc4 [ 6] check_traps [ 7] mov loc11, arg2 [ 10] mov loc12, arg1 [ 13] mov loc13, arg3 [ 16] new_array loc10, loc11, 3, 3 [ 22] get_by_id loc7, loc10, 0 [ 27] new_func_exp loc9, loc4, 0 [ 31] call loc7, loc7, 2, 16 [ 37] get_by_val loc6, loc7, Int32: 1(const0) [ 42] ret loc6 Compilation clamp#CChm91-2-DFG: arg0: predicting OtherObj arg1: predicting BoolInt32 arg2: predicting BoolInt32 arg3: predicting BoolInt32 [ 0] enter [ 1] get_scope loc4 [ 3] mov loc5, loc4 [ 6] check_traps [ 7] mov loc11, arg2 [ 10] mov loc12, arg1 [ 13] mov loc13, arg3 [ 16] new_array loc10, loc11, 3, 3 [ 22] get_by_id loc7, loc10, 0 [ 27] new_func_exp loc9, loc4, 0 [ 31] call loc7, loc7, 2, 16 [ 37] get_by_val loc6, loc7, Int32: 1(const0) [ 42] ret loc6
- deleted 6y ago
  [deleted]
- garmaine 6y ago
  Dude, you are generating random numbers inside the loop. That is going to dominate runtime.
  - saagarjha 6y ago
    I'm not testing runtime, though, I'm testing whether clamp gets optimized.

No. Just things written by web devs. (Shots fired)

I was curious how slow this would be, and here is what JavaScriptCore made of this code: function clamp(n, min, max) { return [min, n, max].sort((a, b) => a - b)[1]; } for (var i = 0; i < 10000000; i++) { clamp(Math.random() | 0, Math.random() | 0, Math.random() | 0); } However, I was pretty disappointed when it seemed to be calling sort each time :( Perhaps I profiled it incorrectly? jsc's profiling data shows that it never hit FTL and nothing ever got inlined. The bytecode for DFG and Baseline is identical: Compilation clamp#CChm91-1-Baseline: arg0: predicting OtherObj arg1: predicting BoolInt32 arg2: predicting BoolInt32 arg3: predicting BoolInt32 [ 0] enter [ 1] get_scope loc4 [ 3] mov loc5, loc4 [ 6] check_traps [ 7] mov loc11, arg2 [ 10] mov loc12, arg1 [ 13] mov loc13, arg3 [ 16] new_array loc10, loc11, 3, 3 [ 22] get_by_id loc7, loc10, 0 [ 27] new_func_exp loc9, loc4, 0 [ 31] call loc7, loc7, 2, 16 [ 37] get_by_val loc6, loc7, Int32: 1(const0) [ 42] ret loc6 Compilation clamp#CChm91-2-DFG: arg0: predicting OtherObj arg1: predicting BoolInt32 arg2: predicting BoolInt32 arg3: predicting BoolInt32 [ 0] enter [ 1] get_scope loc4 [ 3] mov loc5, loc4 [ 6] check_traps [ 7] mov loc11, arg2 [ 10] mov loc12, arg1 [ 13] mov loc13, arg3 [ 16] new_array loc10, loc11, 3, 3 [ 22] get_by_id loc7, loc10, 0 [ 27] new_func_exp loc9, loc4, 0 [ 31] call loc7, loc7, 2, 16 [ 37] get_by_val loc6, loc7, Int32: 1(const0) [ 42] ret loc6

deleted 6y ago
[deleted]
garmaine 6y ago
Dude, you are generating random numbers inside the loop. That is going to dominate runtime.
- saagarjha 6y ago
  I'm not testing runtime, though, I'm testing whether clamp gets optimized.