On Monday, 12 January 2015 at 13:37:19 UTC, ref2401 wrote:
Thanks for the links.
I have shared class instance. There are two threads which can
read/write fields of the class. As i understand i can declare
class as synchronized or i can read/write using
atomicLoad/atomicStore.
What's the difference between these two approaches?
In what circumstances should i consider synchronized classes or
using std.atomic?
synchronized uses locks, and as such is good for (rule-of-thumb)
low contention situations, i.e. you don't have lots of threads
all trying to access the same data at the same time (or few
threads doing lots of repeated access). It has significant
overhead as there is a cost to taking and releasing the lock and
can be very slow under high-contention. Its advantage is that
it's merely difficult to get right.
Using core.atomic and lock-free techniques in general is great
for getting good performance in high-contention situations and/or
reducing overhead in low-contention environments. However, it is
very difficult to get right, very difficult to know if you have
got it right and insanely difficult to debug when things go wrong.
