[cpp-threads] modes

[Peter Dimov]

Peter Dimov wrote:
> Doug Lea wrote:
> 
>> Aside: I haven't checked this in about 3 years, but at the time,
>> incrementing using CAS (with retry) on x86-smps I had around was not
>> reliably slower than locked add.
> 
> On my AMD Athlon 2500+ uniprocessor, CAS is about 4% slower (CAS time
> ~= 1.04 times lock xadd time).
> 
> On an Intel 3.2 GHz with HT uniprocessor, CAS is reportedly 87%
> slower (CAS time ~= 1.87 lock xadd time).
> 
> Dual Intel results maybe tomorrow.

Dual Xeon 3.06 w/ HT: CAS ~= 1.79 lock xadd.