{"id":1977,"date":"2009-09-01T14:57:58","date_gmt":"2009-09-01T18:57:58","guid":{"rendered":"http:\/\/mjtsai.com\/blog\/?p=1977"},"modified":"2014-01-03T09:49:05","modified_gmt":"2014-01-03T14:49:05","slug":"selector-uniquing-in-the-dyld-shared-cache","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2009\/09\/01\/selector-uniquing-in-the-dyld-shared-cache\/","title":{"rendered":"Selector Uniquing in the dyld Shared Cache"},"content":{"rendered":"<p><a href=\"http:\/\/www.sealiesoftware.com\/blog\/archive\/2009\/09\/01\/objc_explain_Selector_uniquing_in_the_dyld_shared_cache.html\">Greg Parker<\/a>:<\/p>\r\n<blockquote cite=\"http:\/\/www.sealiesoftware.com\/blog\/archive\/2009\/09\/01\/objc_explain_Selector_uniquing_in_the_dyld_shared_cache.html\"><p>Snow Leopard&rsquo;s dyld shared cache uniques Objective-C selectors, and Snow Leopard&rsquo;s Objective-C runtime recognizes when the selectors in a shared library are already uniqued courtesy of the shared cache. About half of the runtime&rsquo;s initialization time is eliminated, making warm app launch several tenths of a second faster. Typical memory savings is 200-500 KB per process, adding up to a few megabytes system-wide. When this optimization ships on the iPhone OS side, it&rsquo;s estimated to save 1 MB on a 128 MB device. The iPhone performance team would pay any number of arms and legs for that kind of gain.<\/p><\/blockquote>","protected":false},"excerpt":{"rendered":"<p>Greg Parker: Snow Leopard&rsquo;s dyld shared cache uniques Objective-C selectors, and Snow Leopard&rsquo;s Objective-C runtime recognizes when the selectors in a shared library are already uniqued courtesy of the shared cache. About half of the runtime&rsquo;s initialization time is eliminated, making warm app launch several tenths of a second faster. Typical memory savings is 200-500 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"","apple_news_api_id":"","apple_news_api_modified_at":"","apple_news_api_revision":"","apple_news_api_share_url":"","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[4],"tags":[205,30,210,54,138,71],"class_list":["post-1977","post","type-post","status-publish","format-standard","hentry","category-programming-category","tag-dyld","tag-mac","tag-snowleopard","tag-objective-c","tag-optimization","tag-programming"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/1977","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=1977"}],"version-history":[{"count":1,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/1977\/revisions"}],"predecessor-version":[{"id":8275,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/1977\/revisions\/8275"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=1977"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=1977"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=1977"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}