[PATCH] D16371: [compiler-rt/profile] Added Hostname to .profdata file

[Xinliang David Li via llvm-commits]

This justification is good enough for me :)

thanks,

David

On Thu, Jan 28, 2016 at 6:32 PM, Hal Finkel <hfinkel at anl.gov> wrote:
> ----- Original Message -----
>> From: "Xinliang David Li" <davidxl at google.com>
>> To: reviews+D16371+public+5c64e187738065e7 at reviews.llvm.org
>> Cc: dwatersg at gmail.com, "Eric Christopher" <echristo at gmail.com>, "Duncan P. N. Exon Smith" <dexonsmith at apple.com>,
>> "Vedant Kumar" <vsk at apple.com>, "Hal Finkel" <hfinkel at anl.gov>, "llvm-commits" <llvm-commits at lists.llvm.org>
>> Sent: Thursday, January 28, 2016 8:25:11 PM
>> Subject: Re: [PATCH] D16371: [compiler-rt/profile] Added Hostname to .profdata file
>>
>> On Thu, Jan 28, 2016 at 6:10 PM, Hal Finkel <hfinkel at anl.gov> wrote:
>> > hfinkel added a comment.
>> >
>> > In http://reviews.llvm.org/D16371#338901, @vsk wrote:
>> >
>> >> To clarify, my objection to using guards for this feature wasn't
>> >> cosmetic: is there anything fundamental about MSVC that inhibits
>> >> this feature?
>> >
>> >
>> > There's no uname() (or sys/utsname.h) on Windows. That's a POSIX
>> > function.
>> >
>> >> I see that your lit test tests this patch, but (1) am concerned
>> >> that the usage of uname might break Windows bots, and
>> >
>> >
>> > It would, except that the '// REQUIRES: shell' should cause the
>> > Windows bots to skip the test.
>> >
>> >> (2) wonder whether uname can be used by your scripts directly
>> >> instead of relying on %h-expansion.
>> >
>> >
>> > It is not clear how else to test that the host-name expansion
>> > actually works.
>>
>> I guess Vedant's point is that %h expansion is not strictly needed as
>> the name expansion does not need to be delayed until instrumented
>> binary run -- it can be set ahead of time before the run with $(uname
>> -n) output being put into the name string.  What is the use case in
>> which this would not work?
>
> This does not work for cluster systems, supercomputers, etc. where each executable receives the same input environment (even though they're run on different hosts).
>
> Thanks again,
> Hal
>
>>
>> David
>>
>>
>>
>> >
>> >
>> > http://reviews.llvm.org/D16371
>> >
>> >
>> >
>>
>
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory