Re: [boost] Performance characteristics of Boost mutex

Subject: Re: [boost] Performance characteristics of Boost mutex
From: Edward Diener (eldiener_at_[hidden])
Date: 2014-10-17 22:54:09

On 10/17/2014 4:34 PM, Peter Dimov wrote:
> Philip Bennefall wrote:
>> Hi all,
>>
>> I am detecting some lock contention in my application, and while
>> reading up on this I came across the concept of lightweight mutexes
>> versus supposedly non-lightweight mutexes. I am wondering, can Boosts
>> non-recursive mutex implementation be considered lightweight? In
>> boost/detail I see lightweight_mutex. Should I be using that?
>
> Probably not.
>
> detail::lightweight_mutex is merely a thin wrapper over CRITICAL_SECTION
> on Windows and pthread_mutex on POSIX. It's "lightweight" only in the
> sense that it doesn't require the user to link against a library
> (Boost.Thread).
>
> In general, it doesn't make much sense to talk about a "lightweight"
> mutex if you're talking performance. The "weight" of the mutex doesn't -
> in general - have much to do with its performance (nowadays).

Nonetheless on Windows CRITICAL_SECTION is quite a bit faster than the 
mutex object, probably because it is intraprocess whereas Window mutex 
objects are interprocess.