https://svn.boost.org/trac10/ticket/9480 <p> in libs\filesystem\src\operations.cpp the make_permissions calls path::extension four times, which accounts for pretty much 100% of the cpu cycles outside the OS call of the directory iterators increment function. A better approach would be to get the extension string once and reuse it four times. Even better would be to find the last '.' in the filename and avoid the extra std::string construction. </p> <blockquote> <p> perms make_permissions(const path&amp; p, DWORD attr) { </p> <blockquote> <p> perms prms = fs::owner_read | fs::group_read | fs::others_read; if ((attr &amp; FILE_ATTRIBUTE_READONLY) == 0) </p> <blockquote> <p> prms |= fs::owner_write | fs::group_write | fs::others_write; </p> </blockquote> <p> std::string ext = p.extension().string(); if (BOOST_FILESYSTEM_STRICMP(ext.c_str(), ".exe") == 0 </p> <blockquote> <table class="wiki"> <tr><td> BOOST_FILESYSTEM_STRICMP(ext.c_str(), ".com") == 0 </td></tr><tr><td> BOOST_FILESYSTEM_STRICMP(ext.c_str(), ".bat") == 0 </td></tr><tr><td> BOOST_FILESYSTEM_STRICMP(ext.c_str(), ".cmd") == 0) </td></tr></table> <p> prms |= fs::owner_exe | fs::group_exe | fs::others_exe; </p> </blockquote> <p> return prms; </p> </blockquote> <p> } </p> </blockquote> <p> Or for extra performance (avoids construction of one std::string for the extension at the price of extra nasty code): </p> <blockquote> <p> perms make_permissions(const path&amp; p, DWORD attr) { </p> <blockquote> <p> perms prms = fs::owner_read | fs::group_read | fs::others_read; if ((attr &amp; FILE_ATTRIBUTE_READONLY) == 0) </p> <blockquote> <p> prms |= fs::owner_write | fs::group_write | fs::others_write; </p> </blockquote> <p> const std::string&amp; path_str = p.string(); if (path_str.size() &gt;= 4) { </p> <blockquote> <p> const char* ext = path_str.c_str() + path_str.size() - 4; if (BOOST_FILESYSTEM_STRICMP(ext, ".exe") == 0 </p> <blockquote> <table class="wiki"> <tr><td> BOOST_FILESYSTEM_STRICMP(ext, ".com") == 0 </td></tr><tr><td> BOOST_FILESYSTEM_STRICMP(ext, ".bat") == 0 </td></tr><tr><td> BOOST_FILESYSTEM_STRICMP(ext, ".cmd") == 0) </td></tr></table> <p> prms |= fs::owner_exe | fs::group_exe | fs::others_exe; </p> </blockquote> </blockquote> <p> } return prms; </p> </blockquote> <p> } </p> </blockquote> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/9480 Trac 1.4.3 Adrian Dorr <a.dorr@…> Mon, 09 Dec 2013 13:07:45 GMT https://svn.boost.org/trac10/ticket/9480#comment:1 https://svn.boost.org/trac10/ticket/9480#comment:1 <ul> <li><strong>summary</strong> <span class="trac-field-old">make_permissions slower then it needs to me</span> → <span class="trac-field-new">make_permissions slower then it needs to be</span> </li> </ul> Ticket Daniel Krügler <daniel.kruegler@…> Fri, 31 Oct 2014 23:12:33 GMT