how atomic instruction work?
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xie cui
Sep 17, 2021, 9:25:23 AM9/17/21
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how atomic insturction work in golang at x86/amd64,
I think the atomic insturtion will flush the store buffer and invalid queue of current cpu core,
but I am not sure, does someone know about it?
Ian Lance Taylor
Sep 17, 2021, 3:17:26 PM9/17/21
to xie cui, golang-nuts
functions in that package will ensure sequential consistency of atomic
operationns, but they will not flush the store buffer. See
https://research.swtch.com/gomm .
Ian
xie cui
Sep 21, 2021, 3:54:29 PM9/21/21
to golang-nuts
https://stackoverflow.com/questions/2599238/are-memory-barriers-necessary-for-atomic-reference-counting-shared-immutable-dat
this answer say that:
On x86, it will turn into a lock prefixed assembly instruction, like LOCK XADD.
Being a single instruction, it is non-interruptible. As an added "feature", the lock prefix results in a full memory barrier.
Being a single instruction, it is non-interruptible. As an added "feature", the lock prefix results in a full memory barrier.
In my opinion, full memory barrier means flush store buffer and invalid queue(not very sure, is this right?)
Ian Lance Taylor
Sep 21, 2021, 5:18:46 PM9/21/21
to xie cui, golang-nuts
On Tue, Sep 21, 2021 at 12:54 PM xie cui <cuiw...@gmail.com> wrote:
>
>
> https://stackoverflow.com/questions/2599238/are-memory-barriers-necessary-for-atomic-reference-counting-shared-immutable-dat
> this answer say that:
> On x86, it will turn into a lock prefixed assembly instruction, like LOCK XADD.
> Being a single instruction, it is non-interruptible. As an added "feature", the lock prefix results in a full memory barrier.
>
> In my opinion, full memory barrier means flush store buffer and invalid queue(not very sure, is this right?)
Can you be specific about exactly what you are asking? You originally
>
>
> https://stackoverflow.com/questions/2599238/are-memory-barriers-necessary-for-atomic-reference-counting-shared-immutable-dat
> this answer say that:
> On x86, it will turn into a lock prefixed assembly instruction, like LOCK XADD.
> Being a single instruction, it is non-interruptible. As an added "feature", the lock prefix results in a full memory barrier.
>
> In my opinion, full memory barrier means flush store buffer and invalid queue(not very sure, is this right?)
said "atomic instruction," and my answer was based on the functions
sync/atomic.LoadInt32 and sync/atomic.StoreInt32. Here you seem to be
talking about sync/atomic.AddInt32, which is fine, but let's agree on
what the question is. This is a Go language mailing list, so can you
ask your question about a Go function, rather than about an "atomic
instruction"? Thanks.
Ian
> On Saturday, September 18, 2021 at 3:17:26 AM UTC+8 Ian Lance Taylor wrote:
>>
>> On Fri, Sep 17, 2021 at 6:25 AM xie cui <cuiw...@gmail.com> wrote:
>> >
>> > how atomic insturction work in golang at x86/amd64,
>> > I think the atomic insturtion will flush the store buffer and invalid queue of current cpu core,
>> > but I am not sure, does someone know about it?
>>
>> I assume that you are asking about the sync/atomic package. The
>> functions in that package will ensure sequential consistency of atomic
>> operationns, but they will not flush the store buffer. See
>> https://research.swtch.com/gomm .
>>
>> Ian
>
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robert engels
Sep 21, 2021, 5:23:14 PM9/21/21
to Ian Lance Taylor, xie cui, golang-nuts
To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAOyqgcX-12SQkcow1az%2BPhOYfubvmuD0q72yOc_xOo%3Dia2J_SQ%40mail.gmail.com.
Dan Kortschak
Sep 21, 2021, 6:09:23 PM9/21/21
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