[concurrency-interest] Enforcing total sync order on modern hardware

Marko Topolnik marko at hazelcast.com
Wed Mar 25 05:49:39 EDT 2015


You have confused my complaint as being about the lack of any definition,
whereas I actually complained that there are several competing definitions
used by various sources. The most natural definition, at least for me, is
this:

When an atomic store is performed on a shared variable, no other thread can
observe the modification half-complete.


Source: http://preshing.com/20130618/atomic-vs-non-atomic-operations

---
Marko

On Wed, Mar 25, 2015 at 10:37 AM, Alexander Terekhov <TEREKHOV at de.ibm.com>
wrote:

> try google... quick search yielded
>
> https://books.google.de/books?isbn=1608459578
>
> Michael L. Scott - 2013 - ‎Computers
> Here the problem is not bypassing, but a lack of write atomicity—one thread
> sees the value written by a store and another thread subsequently sees the
> value ...
>
>
> Marko Topolnik <marko at hazelcast.com>@cs.oswego.edu on 25.03.2015 08:07:05
>
> Sent by:        concurrency-interest-bounces at cs.oswego.edu
>
>
> To:     Alexander Terekhov/Germany/IBM at IBMDE
> cc:     concurrency-interest <Concurrency-interest at cs.oswego.edu>
> Subject:        Re: [concurrency-interest] Enforcing total sync order on
> modern
>        hardware
>
>
> On Wed, Mar 25, 2015 at 4:01 AM, Alexander Terekhov <TEREKHOV at de.ibm.com>
> wrote:
>       T1: X = 1;
>       T2: if (X) Y = 1;
>       T3: A = Y; B = X;
>
>       is about atomicity of absolutely independent write T1: X = 1; just
>       like in
>       IRIW.
>
> IRIW requires all writes to be independent, not just one, and I have
> provided a clear argument why that is important (testing for TSO of
> independent writes). So I can't really make sense of your current argument.
>
> BTW "write atomicity" just means that all the constituent bits are observed
> to be written at once. Obviously, you don't have that meaning in mind, but
> it is not crystal-clear what exactly you _do_ mean by it.
>
> ---
> Marko_______________________________________________
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>
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