http://bugzilla.opensuse.org/show_bug.cgi?id=974372 Bug ID: 974372 Summary: memory cache appears to slow the page load Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: x86-64 OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Firefox Assignee: bnc-team-mozilla@forge.provo.novell.com Reporter: jim@boombatower.com QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- After switching from the 13.2 release to the Tumbleweed release, I noticed a significant increase in page load times with Firefox. In addition, page reload times did not decrease even though many items on the page are in the browser cache. The same did not occur with Chromium, for example. Steps to reproduce: Install Firefox; leave its 'config' settings unmodified from the distro packages. In this case, Firefox was on release 42.0 after switching to Tumbleweed and later updated to 44.0.2 when trying to debug this issue. Open Firebug or the built-in Firefox developer toolbox; enable the network tab. Load a page in browser; does not matter the URL. Observe the time to load and reload the page, paying particular emphasis to the start time to load each cache item. Expected results: Based on the Mozilla documentation and other online sources, my understanding is the cache items should not incur time for: blocking, DNS lookup, connecting, sending, waiting and receiving (although there is a positive value shown for waiting time). Further, most of these items should be 'loaded' essentially concurrently (which corresponds to zero times for each task [excluding waiting] mentioned in previous sentence). Actual results: On page reload or any page load that involves cache items, there are staggered start times on each cache item and a lack of time reduction (compared to loading the items for the first time). The cache items are not 'loaded' immediately and concurrently but are staggered, with each subsequent cache item having a later 'request start time since the beginning' (as titled in Firebug) with the delta being roughly equal to the 'waiting' time of the previous item. The end result is a much slower page load, with the delay being 100-500% the time to perform all the other tasks. Example: page loads in 6 seconds versus 1 second. Basis for claim: I have other computers running openSUSE release 13.2 and Firefox release 39.0 and 41.0.2, respectively. Neither exhibits the staggered cache loading nor overall page load issue described above.

From the Mozilla ftp site, I downloaded these binary releases of Firefox:

39.0 41.0.2 42.0 43.0.2 44.0.2 to the "box running openSUSE Tumbleweed and Firefox 44.0.2" and ran each binary on a set of pages from a single site. The timings were consistent in all releases and did not exhibit the staggered start times on each cache item on either initial page load or reload. Running release 44.0.2 from the distro packages continues to exhibit the staggered start times on each cache item and lack of time reduction on page reload. -- You are receiving this mail because: You are on the CC list for the bug.