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wilzbach / tools-test

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gdc compilation performance on the Raspbery Pi leaves to be desired #162

Open wilzbach opened 7 years ago

wilzbach commented 7 years ago

Note: the issue was created automatically migrated from https://issues.dlang.org

Original bug ID: BZ#17093 From: Ion Todirel <iontodirel@gmail.com> Reported version: D2 CC: ibuclaw@gdcproject.org

wilzbach commented 7 years ago

Comment author: Ion Todirel <iontodirel@gmail.com>

gdc seems much slower than gcc on Raspberry Pi, I don't know what other detail to provide

wilzbach commented 7 years ago

Comment author: Ion Todirel <iontodirel@gmail.com>

This is a Raspberry Pi 3

wilzbach commented 7 years ago

Comment author: Ion Todirel <iontodirel@gmail.com>

P.S. running Raspbian Jessie

wilzbach commented 7 years ago

Comment author: Iain Buclaw <ibuclaw@gdcproject.org>

Any comparative examples of C vs. D would be useful. If it's slow on Raspi, then it'll be slow on any other host system, just not as pronounced.

Assuming you mean time to compile, could be any of three components which it's spending most of it's time in.

1) Compiler: If here, try compiling with -v -ftime-report -ftime-report-details, and we'll see if there's any semantic / pass that it is taking longer than others.

2) Assembler: If here, then it's not a bug, and you've just underestimated just how much code is generated. Here's a contrived example: https://goo.gl/Ya6lXB

3) Linker: Again, it's not a bug. But chances am you are linking to druntime/phobos statically, this is would be a very IO and CPU intensive on a poor Raspi. Compiling with -shared-libphobos should sort that out and bring you back up to speed with gcc. (Debian turns on -shared-libphobos by default, but in upstream for now it is still default disabled while it undergoes more testing).