Why slim reader/writer exclusive lock outperformance the shared one?

Question

I have tested the performance of slim reader/writer lock under windows 7 using the codefrom Windows Via C/C++.

The result surprised me that the exclusive lock o

Answer 1

A Windows kernel developer devoted to optimizing locks in Windows told me with regards to performance as a rule of thumb:

1. Use critical sections for most cases for best performance
2. Consider SRW locks if you are reading at least 4:1 vs writing
3. Only use mutexes if your code can absolutely not permit starvation

Obviously there are other aspects about the locks that one should consider:

1. you have to clean up a CS whereas you don't have to clean up a SRW lock
2. CS locks can be taken recursively whereas SRW locks cannot
3. mutexes can synchronize UM and KM, and if you are in KM, CS and SRW locks aren't really an option

So yeah, just favor CS unless reads >>>> writes.