liblf-dev : Message: Re: [liblf-dev] Lock-free ring buffer memory barriers test case

liblf-dev · Lockfree data structure implementers

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Lock-free ring buffer memory barriers test case

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Message #288 of 300 |

Re: [liblf-dev] Lock-free ring buffer memory barriers test case

On Fri, Oct 31, 2008 at 10:34 AM, Bjorn Roche <bjorn@...> wrote:
>
> On Oct 30, 2008, at 5:10 PM, James McCartney wrote:
>
>> On Wed, Oct 29, 2008 at 11:37 AM, Bjorn Roche <bjorn@...>
>> wrote:
>> > Plus, gcc, for example, tends to
>> > insert memory barriers in places, like at function calls.
>>
>> I really don't think so. citation?
>>
>
>
> I can't find a citation right now, so I could be wrong. If I am wrong,
> sorry about that. It's obviously not behavior to count on anway, since
> even if you know you are always working with gcc functions can be
> inlined.

Even with -O0?

Steve

Fri Oct 31, 2008 4:09 pm

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"Stephen Sinclair" <radarsat1@...>

sinclairs828

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Message #288 of 300 |

Expand Messages	Author	Sort by Date
Hi, Can any of you advise a good test case that would demonstrate memory barriers are needed in a lock-free ring buffer ? I mean: a piece of code that would...	oja_i_i	Oct 29, 2008 3:44 am
Many optimizing compilers will make things work, not because they should work, but because optimizers like to remove operations and that tends to make things...	Bjorn Roche bejayoharen	Oct 29, 2008 6:37 pm
... Thanks for your answer. Is this the counter example you mention: http://tech.groups.yahoo.com/group/liblf-dev/message/203 ? -- Olivier Guilyardi / Samalyse...	oja_i_i	Oct 30, 2008 2:12 pm
... Gosh that's hard to read without the tabs! I think that was just a standard ringbuffer, not a proof that memory barriers are needed design. bjorn ... Bjorn...	Bjorn Roche bejayoharen	Oct 30, 2008 3:21 pm
... I really don't think so. citation? --...	James McCartney james_e_mcca...	Oct 30, 2008 9:20 pm
... I can't find a citation right now, so I could be wrong. If I am wrong, sorry about that. It's obviously not behavior to count on anway, since even if you...	Bjorn Roche bejayoharen	Oct 31, 2008 2:34 pm
... Even with -O0? Steve...	Stephen Sinclair sinclairs828	Nov 1, 2008 6:17 am
... I've read so many citations, and other theories about ring buffers and memory barriers. But to me they're useless until someone can write a piece of code...	oja_i_i	Nov 1, 2008 6:17 am
Hello, I just saw this postedon reddit, I'm not sure but I thought it might be relevant to this discussion. ...	Stephen Sinclair sinclairs828	Nov 6, 2008 6:57 am
There are two files in the file section of this list. I scanned the emails of this list quickly and I think they both ran fine for many people and failed for...	Bjorn Roche bejayoharen	Nov 6, 2008 3:18 pm
I don't think so either. I'd be surprised if gcc inserts any memory barriers. But I do remember reading somewhere that a C optimizer probably won't reorder...	Ross Bencina ross_bencina	Nov 1, 2008 6:15 am

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