On my home machine, I've been experimenting with a program named ccache (http://ccache.samba.org.) It's pretty damn nice. Checkout the summary I put together:
The following are tests of ccache (http://ccache.samba.org) on a 2.5.44 kernel compile. The CPU is Intel(R) Pentium(R) 4 CPU 1.70GHz rated at 3391.48 bogomips. All compiles were done with the same .config file. Steps: make mrproper was executed to clean the tree. Then modified the Makefile, prepending 'ccache' to the CC definition. Then: cp ../config/config-2.5.44 .config make oldconfig make dep Finally: make clean make modules make bzImage Results: bzImage modules ccache first run 8:23.75 14:53.48 ccache second run 1:37.72 2:34.94 ccache disabled* 7:37.36 14:52.95 ccache third run 1:47.84 3:00.99 ccache removed 14:54.92 * disabled with 'export CCACHE_DISABLE=true' Cache statistics after the third run. All misses were generated in first run. Hits increased to within about 5 of misses after the second run. The disabled run did not affect it at all. The third run increased the hits to almost double the misses. [todd@trip ~/src/linux-2.5.44/log]$ ccache -s cache hit 2574 cache miss 1296 compile failed 1 not a C/C++ file 21 no input file 28 files in cache 2592 cache size 14.3 Mbytes Then I modified the Makefile, adding ccache back in. Then I changed a few items in the .config and reran: make clean make oldconfig make dep And then the modules and bzImage targets. I wasn't really interested in it being faster. Instead, I wanted to see it register a high percentage of hits and a low percentage of misses. Compare to the previous cache stats: [todd@trip ~/src/linux-2.5.44]$ ccache -s cache hit 3846 cache miss 1302 compile failed 1 not a C/C++ file 28 no input file 36 files in cache 2604 cache size 14.4 Mbytes Notice how cache hits went way up, cache misses incremented only slightly, and the cache size increased slightly. This seems to be desired behavior. This seems like a nice thing to have, at least on build machines. Anybody got any horror stories about this? -- Blue skies... Todd | Get a bigger hammer! | schroom niet--if you consider doing | | http://www.mrball.net | it, stop cosidering and *do* it. | | http://faq.mrball.net | --Wouter Teepe | Linux kernel 2.5.44 2 users, load average: 0.06, 0.25, 0.28
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