Speed Up linking speed / Fast linking on linux.

Question

Hi,

I am building webkit ( 2 Million lines ) after every ten minutes to see the output of my change in it, and linking of webkit on my Machine requires to process 600-700 MB of object files which are there on my hard-disk. That takes around 1.5 minutes. I want to speedup this linking process.

Is there any chance that, I can tell os to keep all the object files in RAM only ( I have 4 GB of ram ). Is there any other way to speed up the linking?

Any ideas or help is appreciated!

Here is a command which takes 1.5 minutes,

http://pastebin.com/GtaggkSc

Answer 1

Try to use a ramdisk

Answer 2

Truthfully I'm not sure I understand the problem but would something like ramfs be of use to you?

Answer 3

Get a SSD Disk for your linux machine. If write performance is still a problem configure the output path to be in a ram disk.

Have you measured how much of the 1.5min is really IO bound? Webkit being so large means that you can run into memory cache trashing. You should try to find out how many L1/L2 cache misses you have. I would suggest that this is a problem. In this case your only hope is that someone at the GCC team looks into this problem.

By the way: Microsoft has the same problem with extreme linker times.

Answer 4

I solved this problem by using tempfs and gold linker.

1). tmpfs: mount directory which contains all the object files as tmpfs.

2). gold linker: using gold linker will make linking 5-6 times fast, with tmpfs advantage speedup will be 7-8 times than normal linking. use following command on ubuntu and your normal linker will get replaced with Gold Linker.

sudo apt-get install binutils-gold

You can find some linking error using gold linker, below thread is a good help on it.

http://stackoverflow.com/questions/3476093/replacing-ld-with-gold-any-experience