Re: Advanced Auto-Dependency Generation and Parallel Execution

[Garrett Cooper]

On Mon, Dec 1, 2008 at 10:06 PM, Paul Smith <address@hidden> wrote:
> On Mon, 2008-12-01 at 18:51 -0800, Garrett Cooper wrote:
>> Another issue is ncurses and how it does it's echo'ing (see the
>> following line from progs/Makefile.in):
>>
>> transform.h :
>>         echo "#define PROG_CAPTOINFO \"$(define_captoinfo)\"" >$@
>>         echo "#define PROG_INFOTOCAP \"$(define_infotocap)\"" >>$@
>>         echo "#define PROG_RESET     \"$(define_reset)\""     >>$@
>>         echo "#define PROG_INIT      \"$(define_init)\""      >>$@
>>
>> Under certain conditions this fails (the bugs who reported the
>> internal bug didn't have a clearcut means for reproducing the issue).
>
> I can't see any possible way that this could fail, unless maybe there
> are multiple instances of make trying to create this same file.  I don't
> accept the assertion that this is real-life race-condition-prone code.
>
> When this fails, what are the symptoms?  Is the transform.h file
> corrupted somehow?  In what way?

I believe that was the case yes, and the problem might have been NFS /
latency related because we do a lot of our development on NFS shares
with a large number of users, and overtaxed systems.

If that's truly the case, this is more of a bi-product of an NFS level
caching and ordering of messages issue.

[OT]
Still... if things are going to be rather static like that and not
going to change across compiles, why not just generate the file once
and leave it as-is?
[/OT]

-Garrett