<div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Mar 14, 2013 at 6:57 PM, Richard Purdie <span dir="ltr"><<a href="mailto:richard.purdie@linuxfoundation.org" target="_blank">richard.purdie@linuxfoundation.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div id=":2lm">Currently, various standard library operations like os.walk(),<br>
os.path.isdir() and os.path.islink() each call stat or lstat which<br>
involves a syscall into the kernel. There is no caching since they could<br>
conceivably have changed on disk. The result is that for something like<br>
the do_package task of the kernel we're spending over two minutes making<br>
868,000 individual stat calls for 23,000 files. This is suboptimal.<br>
<br>
This patch adds lib/oe/cachedpath.py which are a set of replacement<br>
functions for these operations which use cached stat data rather than<br>
hitting the kernel each time. It gives a nice performance improvement<br>
halving the build time of the kernel do_package.<br>
<br>
Signed-off-by: Richard Purdie <<a href="mailto:richard.purdie@linuxfoundation.org">richard.purdie@linuxfoundation.org</a>></div></blockquote></div><br>Have you considered having the initcache() return a cache object, either with the rest as methods on it, or pass that in? I think it'd be substantially cleaner than messing with globals, particularly given with globals we tend to have issues with cache lifetime and invalidation — if the cache was returned, it would go away when the object gets collected.<br>
-- <br>Christopher Larson</div></div>