Optimise the balance function #1771
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I stumbled upon it by accident and couldn't help myself. This is probably just a
drop in the bucket.
Microbenchmarks with an UTxO with 1,000,000 entries:
Before:
time 47.36 ms (45.38 ms .. 48.76 ms)
0.997 R² (0.994 R² .. 0.999 R²)
mean 47.86 ms (47.23 ms .. 48.89 ms)
std dev 1.582 ms (1.131 ms .. 2.370 ms)
After:
time 18.72 ms (18.53 ms .. 18.91 ms)
0.999 R² (0.998 R² .. 1.000 R²)
mean 18.69 ms (18.58 ms .. 18.86 ms)
std dev 305.1 μs (233.6 μs .. 431.3 μs)
| balance :: Crypto crypto => UTxO crypto -> Coin | ||
| balance (UTxO utxo) = foldr addCoins 0 utxo | ||
| balance :: UTxO crypto -> Coin | ||
| balance (UTxO utxo) = fromIntegral $ Map.foldl' addCoins 0 utxo |
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Note that I use Word64 to sum them and only convert to Coin at the end. Is this fine or do we expect an overflow?
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a property of the system is that there are never more than 45 * 10 ^ 15 coins in this map, so 2 ^ 64 is more that enough. that said, if there ever were a bug, this could obfuscate the problem.
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a property of the system is that there are never more than 45 * 10 ^ 15 coins in this map, so 2 ^ 64 is more that enough.
I see.
that said, if there ever were a bug, this could obfuscate the problem.
So what do you prefer?
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FYI, when summing using Coin instead of Word64:
time 36.17 ms (35.04 ms .. 37.35 ms)
0.998 R² (0.996 R² .. 0.999 R²)
mean 36.61 ms (36.15 ms .. 37.22 ms)
std dev 1.112 ms (812.8 μs .. 1.637 ms)
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I don't have a strong preference, I'm just making sure we all have the same understanding. Thank you for helping out with the performance @mrBliss !
I stumbled upon it by accident and couldn't help myself. This is probably just a
drop in the bucket.
Microbenchmarks with an UTxO with 1,000,000 entries:
Before:
After: