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

[Zachary Turner]

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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>
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