[Lldb-commits] [lldb] r236892 - Enable thread-safe logging.

[Pavel Labath]

Sounds good to me.

On 11 May 2015 at 16:51, Zachary Turner <zturner at google.com> wrote:
> If the reason is to avoid those race conditions, perhaps the default value
> should be threadsafe, and the option should disable thread safety.
>
> On Mon, May 11, 2015 at 8:40 AM Pavel Labath <labath at google.com> wrote:
>>
>> I think the reason is that when you are debugging a race condition,
>> the added synchronization resulting from logging can make the problem
>> go away as soon as you start investigating it, which can be quite
>> annoying.
>>
>> BTW, there is a way to do atomic writes (at least on posix systems, I
>> don't know if there is a windows equivalent) without locking: write
>> the string to a temporary buffer in memory (as you do now), and then
>> write it to a file which was opened with O_APPEND with a single system
>> call. Your implementation probably already does this, so all you need
>> to do is make sure O_APPEND is set.
>>
>> cheers,
>> pl
>>
>>
>>
>> On 11 May 2015 at 16:23, Zachary Turner <zturner at google.com> wrote:
>> > +greg. I'm not sure either tbh, if there's no contention the cost of
>> > acquiring the mutex should be free, and if there is contention then the
>> > lock
>> > is required.
>> >
>> > On Mon, May 11, 2015 at 7:29 AM Ed Maste <emaste at freebsd.org> wrote:
>> >>
>> >> On 8 May 2015 at 14:50, Zachary Turner <zturner at google.com> wrote:
>> >> > Author: zturner
>> >> > Date: Fri May  8 13:50:54 2015
>> >> > New Revision: 236892
>> >> >
>> >> > URL: http://llvm.org/viewvc/llvm-project?rev=236892&view=rev
>> >> > Log:
>> >> > Enable thread-safe logging.
>> >>
>> >> Thanks for fixing this up Zach.
>> >>
>> >> This raises a question though, going back to the original introduction
>> >> of logging support -- why is this an option at all, never mind a user
>> >> facing option? It's particularly odd that we default to thread-safe,
>> >> unless any other options are specified. It seems to me we should just
>> >> remove the thread-unsafe path.
>> >
>> >
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