snapshot: use per-Snapshot PRNGs to reduce lock contention + cleanup #35
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This commit changes the snapshot package to use per-Snapshot PRNGs instead of a single global PRNG - this reduces lock contention. Additionally, it cleans up the code a bit by changing map accesses to check if the result if nil instead of doing the "val, ok" check. These changes are pretty minor and are mostly a nit.
mxr
approved these changes
Aug 19, 2020
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| func (s *Snapshot) FeatureEnabled(key string, defaultValue uint64) bool { | ||
| return defaultRandomGenerator.Random()%100 < min(s.GetInteger(key, defaultValue), 100) | ||
| return s.rand.Uint64()%100 < min(s.GetInteger(key, defaultValue), 100) |
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Should we use Intn(100) for readability? Is that the same thing?
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| ret := make([]string, 0, len(s.entries)) | ||
| for key := range s.entries { | ||
| ret = append(ret, key) |
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Suggested change
| ret := make([]string, 0, len(s.entries)) | |
| for key := range s.entries { | |
| ret = append(ret, key) | |
| ret := make([]string, len(s.entries)) | |
| for i, key := range s.entries { | |
| ret[i] = key |
This is faster (?)
Contributor
Author
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It would be if s.entries we're a slice, but it's a map so this will actually fail to compile.
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| const a = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" | ||
| const key = a + a |
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Why not initialize key to be a literal "aaaaa....a"?
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| r.mu.Lock() | ||
| x := r.rr.Int63() | ||
| r.mu.Unlock() |
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Should/could we use a threadsafe source instead of locking? Or will a threadsafe source also lock under the hood?
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| func (n *Nil) FeatureEnabled(key string, defaultValue uint64) bool { | ||
| return defaultRandomGenerator.Random()%100 < min(defaultValue, 100) | ||
| return nilRandom.Uint64()%100 < min(defaultValue, 100) |
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This commit changes the snapshot package to use per-Snapshot PRNGs
instead of a single global PRNG - this reduces lock contention.
Additionally, it cleans up the code a bit by changing map accesses to
check if the result if nil instead of doing the "val, ok" check.
These changes are pretty minor and are mostly a nit.