There's no single, simple way to turn logging off and/or not touch disk at all. We do a lot of I/O on the main thread, and we should probably be smarter about the defaults here. I'm going to propose that we default to not logging anything, except for the add-on, which is our primary dev channel. Users experiencing problems should be able to flip the pref easily and get details back.

this hurts alot on mobile.

This patch uses a pref to enable the file-based logging in Sync. The setting defaults to enabled, so no changes are needed for desktop Firefox. Fennec can add the pref to its mobile.js, or we can add a services pref file. Using this patch, I timed the initial login durations on my N900, using the "weave:service:login:start" and "weave:service:login:finish" notifications as markers: with file logging: 1987ms (avg of 5 runs) without file logging: 1357ms (avg of 5 runs) Looks like we could save ~630ms on N900 with this patch. Note: subsequent logins show only very small, if any, improvements. The only real improvements can during initial login. I could do some actual sync duration timing too, but I'm not sure how comparable syncs are to each other.

Comment on attachment 482159 [details] [diff] [review] patch I would like this defaulted to false in this code, and set to true in http://mxr.mozilla.org/services-central/source/fx-sync/addon/AddonGlue.js#62 so that it's only enabled for desktop users with the add-on, but not for users of built-in sync. r=me with those changes

Patch to enable logging in the add-on

Comment on attachment 482159 [details] [diff] [review] patch >+ let enabled = true; >+ try { >+ enabled = Svc.Prefs.get("log.appender.debugLog.enabled"); >+ } catch(e) {} This can be written as let enabled = Svc.Prefs.get("log.appender.debugLog.enabled", true) Svc.Prefs never throws but lets you provide fallback values if the pref doesn't exist. The fallback should probably be "false" here as per mconnor's review comments.

(In reply to comment #5) > Comment on attachment 482159 [details] [diff] [review] > patch > > >+ let enabled = true; > >+ try { > >+ enabled = Svc.Prefs.get("log.appender.debugLog.enabled"); > >+ } catch(e) {} > > This can be written as > > let enabled = Svc.Prefs.get("log.appender.debugLog.enabled", true) > > Svc.Prefs never throws but lets you provide fallback values if the pref doesn't > exist. The fallback should probably be "false" here as per mconnor's review > comments. Thanks! Changing for checkin: let enabled = Svc.Prefs.get("log.appender.debugLog.enabled", false);

pushed both patches into http://hg.mozilla.og/services/fx-sync with nits fixed: http://hg.mozilla.org/services/fx-sync/rev/92c6ee7d6618 The next fx-sync merge will move this into m-c

verified with recent nightly builds of minefield