Opt #110 Optimize memory cache's singleflight performance #111
Conversation
| /* cache hit */ | ||
| return (Ok(result), cache_state); | ||
| } | ||
|
|
There was a problem hiding this comment.
If I understand correct, this is the case following match lockers.get(&hashed_key) code logic can handle, if another one already added a same hashed_key just before lockers.write().
There was a problem hiding this comment.
suppose there are two threads(coroutine) t1 t2
t1 get data -> None
t1 get container read lock, get CacheLock -> None
t1 get container write lock, insert CacheLock
t1 lookup data
t2 get data -> None
t2 pause for some reason such as thread switching
t1 put lookuped data
t1 get container write lock, remove CacheLock
t2 resume and get container read lock, get CacheLock -> None
t2 get container write lock, insert another CacheLock
t2 lookup data
So it is waste that t2 lookup data in this situation.
Double check should be done when get write lock like thread-safe lazy initialization.
Hi,
This PR is refered #110
Optimize memory cache's singleflight performance #110
Thanks