[llvm-dev] Commit module to Git after each Pass

[Philip Reames via llvm-dev]

The most likely answer is that the printer used by print-after-all is 
slow.  I know there were some changes made around passing in some form 
of state cache (metadata related?) and that running printers without 
doing so work, but are dog slow.  I suspect the print-after-all support 
was never updated.  Look at what we do for the normal IR emission "-S" 
and see if print-after-all is out of sync.

Philip


On 03/15/2018 08:45 AM, Alexandre Isoard via llvm-dev wrote:
> Huh. Great! 😁
>
> I don't believe my poor excuse from earlier (else we should map all 
> pipes into files!), but I'm curious why we spend less time in system 
> mode when going through file than pipe. Maybe /dev/null is not as 
> efficient as we might think? I can't believe I'm saying that...
>
> On Thu, Mar 15, 2018, 08:25 Fedor Sergeev <fedor.sergeev at azul.com 
> <mailto:fedor.sergeev at azul.com>> wrote:
>
>     Well, git by itself is so focused on performance, so its not
>     surprising
>     to me that even using git add/git commit does not cause
>     performance penalties.
>
>
> Sure, but still, I write more stuff (entire module) into a slower 
> destination (file). Even ignoring git execution time it's counter 
> intuitive.
>
> The only difference is that while I write more, it overwrite itself 
> continuously, instead of being a long linear steam. I was thinking of 
> mmap the file instead of going through our raw_stream, but maybe 
> that's unnecessary then...
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180315/a0a74848/attachment.html>