It's more like a thinking practice that occurred to me while working, so
yeah that kind of education is not what I need on this one. :)
On Tuesday, July 2, 2019 at 1:31:00 AM UTC+8, Martin Thompson wrote:
>
> When programming with threads you have to respect the language memory
> model to have a chance of creating correct code. I don't get what point you
> are trying for here.
>
> If your goal is to learn then maybe read up on memory models and compiler
> optimisations. The people on SO might have a point ;-)
>
> On Monday, 1 July 2019 17:05:47 UTC+1, w jp wrote:
>>
>> I'm not sure if this post fits here coz it's more about concurrency. I'm
>> trying to reasoning if I could get by without atomic or other
>> synchronization
>> in this case.
>>
>> So I have two go routines:
>>
>> var sequence int64
>>
>> // writer
>> for i := sequence; i < max; i++ {
>> doSomethingWithSequence(i)
>> sequence = i
>> }
>>
>> // reader
>> for {
>> doSomeOtherThingWithSequence(sequence)
>> }
>>
>> And here're some potential risks I can think of:
>>
>>
>> 1.
>>
>> reordering (for the writer, updating sequence happens before
>> doSomething) could happen, *but I can live with that.*
>> 2.
>>
>> sequence is not properly aligned in memory so the reader might
>> observe a partially updated sequence. Running on (recent kernel)
>> linux with x86_64, can we rule that out?
>> 3.
>>
>> go compiler 'cleverly optimizes' the reader, so the access to i never
>> goes to memory but 'stayed' in a register. Is that possible in go?
>> 4.
>>
>> Anything else?
>>
>> PS: I posted same thing on SO but people seem to be more focused on
>> educating me about not going there, but that's really not my point.
>>
>
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