But but... "d8 --cache=code --trace_parse" doesn't even use the parse cache, it uses the code cache! Why are you running with --cache=code?
On Tue, Dec 9, 2014 at 10:55 PM, Cullinan, Ian <[email protected]> wrote: > (Emailing directly since mail sent by codereview.chromium.org for > @amazon.com addresses gets stuck in spam filters. My apologies if you get > this twice.) > > > Q: I wonder whether we need to / should modify the "preparse data". Would > > it be > > better to keep it as is, so that it just contains the positions of the > >lazy > > top-level functions and no identifiers? (I don't know the answer.) > > Adding the identifiers to the preparse data gets us a pretty big win on > warm parsing times. I don't have access to morejs so I can't try that, but > what I have been doing is running `d8 --cache=code --trace_parse` with > some popular JavaScript files from the web and looking at how long parsing > takes with and without the preparse data, with and without my change (on > my desktop, times in milliseconds, median of five runs): > > before after > cold warm cold warm > http://connect.facebook.net/en_US/all.js 8.2 7.9 5.1 0.7 > http://[1]/analytics.js 1.9 1.7 1.7 0.5 > http://b.scorecardresearch.com/beacon.js 0.1 0.02 0.1 0.02 > http://a.disquscdn.com/embed.js 1 0.04 1 0.04 > http://www.google-analytics.com/ga.js 3 2.8 2.6 0.6 > http://[2]/jquery/1.7.2/jquery.min.js 5.8 5.6 4.1 0.9 > http://[3]/pagead/js/lidar.js 3.6 3.3 2.8 0.7 > http://[3]/pagead/osd.js 3.1 2.9 2.5 0.6 > http://platform.twitter.com/widgets.js 2.5 0.25 2.5 0.25 > > [1] www.google-analytics.com > [2] ajax.googleapis.com/ajax/libs > [3] pagead2.googlesyndication.com > > As you can see, it's the same or better in every case (0-38% speedup cold, > 0-91% speedup with the preparse data). It's a particularly large win on > modern JavaScript libraries like jQuery which make extensive use of > closures to avoid polluting the global scope. > > Here's the numbers for the size of the preparse data (in bytes): > > before after > http://connect.facebook.net/en_US/all.js 20 15260 > http://[1]/analytics.js 20 14500 > http://b.scorecardresearch.com/beacon.js 60 76 > http://a.disquscdn.com/embed.js 340 468 > http://www.google-analytics.com/ga.js 20 23300 > http://[2]/jquery/1.7.2/jquery.min.js 20 17820 > http://[3]/pagead/js/lidar.js 20 21384 > http://[3]/pagead/osd.js 20 18744 > http://platform.twitter.com/widgets.js 1120 1560 > > The extra preparse data is only significant in the cases where it's buying > us a large speedup. > > > >https://codereview.chromium.org/641283003/ > > -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
