Re: [ccache] BSDiff for cache objects

2012-11-12 Thread Jürgen Buchmüller
Am Montag, den 12.11.2012, 13:49 +0200 schrieb Bogdan Harjoc: Basically, before writing a new object file, ccache could find a similar object in the cache (based on object-code or source-code hashes for example) The main goal of most hashes is to give very distinct results even for even small

Re: [ccache] BSDiff for cache objects

2012-11-12 Thread Bogdan Harjoc
On Mon, Nov 12, 2012 at 2:30 PM, Jürgen Buchmüller pullm...@t-online.dewrote: Am Montag, den 12.11.2012, 13:49 +0200 schrieb Bogdan Harjoc: Basically, before writing a new object file, ccache could find a similar object in the cache (based on object-code or source-code hashes for example)

Re: [ccache] BSDiff for cache objects

2012-11-12 Thread Bogdan Harjoc
On Mon, Nov 12, 2012 at 3:39 PM, Andrew Stubbs a...@codesourcery.com wrote: On 12/11/12 11:49, Bogdan Harjoc wrote: Alternatively, a compact operation could be run periodically, that compresses the cache using the same approach. Is cache size/capacity a very big issue for you? No but

Re: [ccache] BSDiff for cache objects

2012-11-12 Thread Andrew Stubbs
On 12/11/12 14:08, Bogdan Harjoc wrote: No but there is room for improvement. This could be optional, like a CCACHE_COMPRESS that saves 99% instead of 40% when I routinely recompile 20 kernel branches, for example (v2.6.x, 3.0.x, 3.4.x, -git, -next, -ubuntu, etc). I realise that the more

Re: [ccache] BSDiff for cache objects

2012-11-12 Thread Bogdan Harjoc
Initial results from a small .ccache (3.0) dir: - 6476 objects - 300MB - probably about 500-1000 compiles/recompiles of around 100 small to large projects The test was: 1. Find the candidates for compression, based on: objdump -t | grep g (defined symbols). If two objects had at least 4