Re: [PATCH v2] Single threaded stdio optimization

[Szabolcs Nagy <szabolcs dot nagy at arm dot com>]

On 07/07/17 16:02, Szabolcs Nagy wrote:
> On 07/07/17 14:38, Szabolcs Nagy wrote:
>> On 07/07/17 13:38, Florian Weimer wrote:
>>> This patch breaks the attached test case.  Not all stream objects are
>>> linked into the global list, so the locking upgrade doesn't happen for
>>> some of them.
>>>
>>
>> i thought all files need to be flushed on exit
>> or on fflush(0), if glibc does not do that that's
>> observably non-conforming.
>>
>>> The global list management is quite expensive because the list is
>>> single-linked, so we can't just add all stream objects when not yet
>>> running multi-threaded.
>>>
>>> I fear that this patch may have to be backed out again, until we can
>>> address these issues.
>>>
>>
>> i can back it out, or try to create all the
>> problematic files with the optimization-disabling
>> flag set (in case that's simple.. will look into
>> it in a minute).
>>
> 
> it seems both changing the optimization flag or adding
> these streams to the list are easy.
> 
> i think glibc should just fix the open_memstream bug,
> https://sourceware.org/bugzilla/show_bug.cgi?id=21735
> i'll work on a patch.
> 
> (i don't expect a large number of open/close memstream
> operations, so it should not have a huge impact)
> 

sorry, i cannot work on this until monday,
i hope it's ok to leave multithread open_memstream
broken for a few days.