From patchwork Sun Mar 11 14:36:44 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [bitbake-devel] codeparser: Call intern over the set contents for better cache performance Date: Sun, 11 Mar 2012 14:36:44 -0000 From: Richard Purdie X-Patchwork-Id: 23021 Message-Id: <1331476604.15192.2.camel@ted> To: bitbake-devel See the comment in the code in the commit for more information. Signed-off-by: Richard Purdie --- lib/bb/codeparser.py | 21 +++++++++++++++++++++ 1 files changed, 21 insertions(+), 0 deletions(-) diff --git a/lib/bb/codeparser.py b/lib/bb/codeparser.py index 04a34f9..af2e194 100644 --- a/lib/bb/codeparser.py +++ b/lib/bb/codeparser.py @@ -98,6 +98,12 @@ def parser_cache_save(d): bb.utils.unlockfile(lf) bb.utils.unlockfile(glf) +def internSet(items): + new = set() + for i in items: + new.add(intern(i)) + return new + def parser_cache_savemerge(d): cachefile = parser_cachefile(d) if not cachefile: @@ -133,6 +139,21 @@ def parser_cache_savemerge(d): data[1][h] = extradata[1][h] os.unlink(f) + # When the dicts are originally created, python calls intern() on the set keys + # which significantly improves memory usage. Sadly the pickle/unpickle process + # doesn't call intern() on the keys and results in the same strings being duplicated + # in memory. This also means pickle will save the same string multiple times in + # the cache file. By interning the data here, the cache file shrinks dramatically + # meaning faster load times and the reloaded cache files also consume much less + # memory. This is worth any performance hit from this loops and the use of the + # intern() data storage. + # Python 3.x may behave better in this area + for h in data[0]: + data[0][h]["refs"] = internSet(data[0][h]["refs"]) + data[0][h]["execs"] = internSet(data[0][h]["execs"]) + for h in data[1]: + data[1][h]["execs"] = internSet(data[1][h]["execs"]) + p = pickle.Pickler(file(cachefile, "wb"), -1) p.dump([data, PARSERCACHE_VERSION])