2012/1/2 Gael Varoquaux <gael.varoqu...@normalesup.org>: > On Mon, Jan 02, 2012 at 07:18:24PM +0100, Gael Varoquaux wrote: >> > BTW, another cleaner, faster way to empty the OS filesystem cache is this: > >> > sudo echo 3 | sudo tee /proc/sys/vm/drop_caches > >> > [ from http://ubuntuforums.org/showthread.php?t=589975 ] > >> That's useful! > > And it works much better to clean the cache. The results with this method > differ a bit, and I trust them much more. > > I have uploaded the graphes on my blog post draft. The gain in reading > time due to compression seems a bit smaller. I believe this is because > compression was helping the data to stay in cache, but I am still > wrapping my head around the results.
With this way of cleaning the OS cache you can get much better estimations for reading because you can be certain that the OS cache is not getting into the game (a thing that I don't know how to do for writing). And the small gains for fast compressor like Blosc is due to the fact that heavier compressors like zlib allows to compress more, so the disk has to work less to deliver the same data. -- Francesc Alted ------------------------------------------------------------------------------ Write once. Port to many. Get the SDK and tools to simplify cross-platform app development. Create new or port existing apps to sell to consumers worldwide. Explore the Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join http://p.sf.net/sfu/intel-appdev _______________________________________________ Pytables-users mailing list Pytables-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pytables-users
