Commits on Oct 14, 2021

1. store/cachekv: reduce growth factor for iterator ranging using binary… …

   … searches
   
   This change takes the observation that previous dbm.IsKeyInDomain
   which searches for [start, end) was performing too many byteslice
   comparisons. Instead we start off by sorting all the values in the
   store.unsortedCache, and then apply a modified binary search to
   look for values that fall within the domain [start, end)
   The procedure involves:
   * iterating over all items to build a list of all keys -- O(n)
   * invoking sort.Strings immediately, of which
   we anyways eventually invoke sort.Slice(unsorted, ...) which uses
   Quicksort -- O(nlog(n)) or O(n^2) worst case
   * invoking modified binary search which is O(log(n)) * 2 ~ O(log(n))
   to search for the [start, end) range indices
   
   for a total approximate complexity of:
   Best case:  O(n) + O(n(log(n))) + O(log(n)) ~= O(nlog(n))
   Worst case: O(n) + O(n^2) + O(log(n))       ~= O(n^2)
   
   instead of previously:
   * iterating over all the unsorted items and invoking dbm.IsKeyInDomain:
   bytes.Compare ~ O(n) + O(n*s*e) where s -- len(start), e -- len(end)
   for overall complexity of O(n*s*e)
   * invoking sort.Slice(unsorted, ...) which uses
   Quicksort -- O(nlog(n)) or O(n^2) worst case
   
   for a total approximate complexity of:
   Best case:  O(n) + O(n*s*e) + O(nlog(n)) ~= O(n*s*e) ~ O(n^2)
   Worst case: O(n) + O(n*s*e) + O(n^2)     ~= O(n*s*e) ~ O(n^2)
   
   Ordinarily we'd combine the n*s*e to be n*m, but really the comparisons
   between (start & key, end & key) are profound that it makes sense to
   keep them as factors. The overall benchmark results vindicate our choice
   of isolating the factors (n*s*e)
   
   The benchmarks show that as the number of keys to iterate grows, the
   new code grows gracefully in a somewhat linear growth, notice for
   CAcheKVStoreIterator*, when we go from:
   * 1,000 to 10,000 keys: 120us->1,600us (13X) old vs 95us->900us (9.47X) new
   * 50,000 to 100,000 keys: 19ms->100ms (5.3X) old vs 5.5ms->17ms (3X) new
   ```shell
   time/op
   GetValidator-8	              5.8ms ± 2%    4.7ms ± 1%	-17.69%	(p=0.000 n=10+10)
   OneBankSendTxPerBlock-8	      3.2ms ± 2%    2.8ms ± 1%	-10.80%	(p=0.000 n=7+10)
   OneBankMultiSendTxPerBlock-8  3.1ms ± 3%    2.9ms ± 2%	-8.36%	(p=0.000 n=10+10)
   AccountMapperSetAccount-8     8.6µs ± 1%    7.8µs ± 1%	-9.74%	(p=0.000 n=10+10)
   CacheKVStoreIterator500-8     64µs ± 6%	    51µs ± 6%	-19.22%	(p=0.000 n=10+9)
   CacheKVStoreIterator1000-8    0.12ms ± 4%   95µs ± 4%	-19.55%	(p=0.000 n=10+10)
   CacheKVStoreIterator10000-8   1.6ms ± 4%    0.90ms ± 1%	-42.11%	(p=0.000 n=10+10)
   CacheKVStoreIterator50000-8   19ms ± 5%	    5.5ms ± 1%	-71.35%	(p=0.000 n=10+10)
   CacheKVStoreIterator100000-8  0.10s ± 23%   17ms ± 7%	-83.44%	(p=0.000 n=10+10)
   CacheKVStoreGetNoKeyFound-8   1.3µs ± 6%    0.90µs ± 3%	-31.19%	(p=0.000 n=9+9)
   CacheKVStoreGetKeyFound-8     0.66µs ± 6%   0.56µs ± 2%	-14.81%	(p=0.000 n=10+9)
   
   alloc/op
   B/op
   BlockProvision-8	     0.11kB ± 0%    0.10kB ± 0%	-7.14%	(p=0.000 n=10+10)
   CacheKVStoreIterator50000-8  0.89MB ± 6%    0.53MB ± 1%	-40.85%	(p=0.000 n=10+10)
   CacheKVStoreIterator100000-8 6.3MB ± 23%    1.6MB ± 6%	-74.17%	(p=0.000 n=10+10)
   CacheKVStoreGetNoKeyFound-8  0.26kB ± 0%    0.23kB ± 1%	-11.53%	(p=0.000 n=10+8)
   
   allocs/op (count)
   AccountMapperSetAccount-8    42 ± 0%	    38 ± 0%	-9.52%	(p=0.000 n=10+10)
   BlockProvision-8	     6.0 ± 0%	    5.0 ± 0%	-16.67%	(p=0.000 n=10+10)
   CacheKVStoreIterator1000-8   14 ± 0%	    13 ± 0%	-7.14%	(p=0.002 n=8+10)
   CacheKVStoreIterator10000-8  0.15k ± 2%	    76 ± 1%	-49.00%	(p=0.000 n=7+10)
   CacheKVStoreIterator50000-8  8.9k ± 11%	    2.0k ± 2%	-77.60%	(p=0.000 n=10+10)
   CacheKVStoreIterator100000-8 0.10M ± 26%    13k ± 12%	-86.89%	(p=0.000 n=10+10)
   CacheKVStoreGetNoKeyFound-8  5.0 ± 0%	    4.0 ± 0%	-20.00%	(p=0.000 n=10+10)
   ```
   
   Note: Purposefully using a commit off master that doesn't
   include the buggy code that caused x/bank.BenchmarkOneBank* to fail
   per issue #10023
   
   Updates #9876

   

   odeke-em committed Oct 14, 2021
   Configuration menu

   • View commit details
   • Copy full SHA for 3ab2006
   • Browse repository at this point

   Copy the full SHA

   3ab2006 View commit details

   Browse the repository at this point in the history