Session Restore PSA

Thanks to efforts of many people in the Mozilla community, combined with tools like DTrace, we seem to be awash in performance data and awareness these days. And in the wonderment of this new visiblity, Rob Sayre and Brendan Gregg noticed that Session Restore was responsible for a significant portion of page-load time! (/me takes an anxious bow, and dodges the tomatoes)

There are a couple of opportunities for improvement, chronicled here. The first approach we’re trying out is to save and restore less back-history for each tab. Easy to implement, but it wasn’t the first choice since it decreased the utility of the feature… or so we thought, until Alex Polvi provided some data indicating that users very rarely go back further than 6 steps.

The change that landed today will reduce saving of back-history to 10 pages, from a default of 50. You can set the browser.sessionstore.max_tab_back_history pref to -1 if you want all tab history restored.

Comment on the bug if you’re one of the <1% who go back beyond 10, and are truly disgruntled about this change. Or better yet, fix my patch to cache tab history🙂


5 Comments on “Session Restore PSA”

  1. George Deka says:

    My question is does the change effect normal behavior or only the history that we store for session restore.

    On session restore i very rarely go back from the page it loads.

  2. dietrich says:

    George: This applies only to tab history for session restore. It does not apply to tab history while running Firefox, nor to the fastback cache.

  3. Jesper Kristensen says:

    Does it only affect Crash restore or does it also affect Restart and the restore home page?

  4. dietrich says:

    Jesper: Yes, this affects any tab that is restored after a restart.

  5. beteendeterapi…

    Att ta hjälp av leg psykologer och få terapi är knappast något att skämmas för numera. Vanligare att folk mår dåligt och behöver coacher och sånt. Alla har problem under livet så det är OK att ta emot hjälp….


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s