mfinkle and I were discussing browser DB perf today, and whether it was worth exploring improvements (e.g., free-text indexing, better representations, query tuning).
I added some logging (the precursor of telemetry for this: Bug 1021922) and did some trivial timing on my phone. The phone: HTC One M7. Quad-core 1.7GHz, 2GB RAM. This is last year's top model, still a relatively high-spec phone. I set up Sync versus my real desktop data (a few hundred bookmarks, normal desktop history) and let it complete. Launching Fennec spams this (as we add default data and thus have to reload the cursor): 06-06 18:22:00.331 D/GeckoTopSitesPanel(24012): TopSitesLoader.loadCursor() took 198msec. 06-06 18:22:00.821 D/GeckoTopSitesPanel(24012): TopSitesLoader.loadCursor() took 86msec. 06-06 18:22:01.101 D/GeckoTopSitesPanel(24012): TopSitesLoader.loadCursor() took 204msec. 06-06 18:22:01.562 D/GeckoTopSitesPanel(24012): TopSitesLoader.loadCursor() took 129msec. Typing "bug": 06-06 18:23:24.470 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 194msec. 06-06 18:23:24.741 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 62msec. 06-06 18:23:24.821 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 52msec. Typing "wiki": 06-06 18:23:40.407 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 193msec. 06-06 18:23:40.648 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 69msec. 06-06 18:23:41.038 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 69msec. 06-06 18:23:41.719 D/GeckoSearchLoader(24012): SearchLoader.loadCursor() took 73msec. Hitting Home then re-loading (showing Top Sites again): 06-06 18:26:12.450 D/GeckoTopSitesPanel(24012): TopSitesLoader.loadCursor() took 135msec. So: a one-character match (which ends up as a view/table walk) takes about 200msec, and every character thereafter updates in less than 100msec (but we're not smart about that: Bug 979121). Loading Top Sites with a totally warm cache takes 135msec (plus processing time, favicons, etc. etc., which is why the wall clock times are about double the reported cursor load times). A clean profile -- no data at all -- takes somewhere around 30-80msec to do the same queries with zero results. Some of that is fixed overhead, and some is query parsing and planning that we can improve. In my opinion: quarter-second+ responsiveness for top sites and for searches, on a high-end phone (with no add-ons, no other big DBs, just non-trivial browsing data) means we have opportunities for improvement, especially on low-end devices. The gap between <100msec and 250msec+ is enough to turn "snappy" into "acceptable", or "acceptable" into "annoyingly slow". I did not even attempt this with a low-end ARMv6 phone: not enough space. Telemetry will give us a broader picture there. But it's probably fair to double, or worse, particularly on devices that don't have a surfeit of cores and fast memory (more contention). I don't know how accurate my timing points are; async cursor loading makes it kinda challenging to say exactly when work finishes. That'll come up in review, no doubt! -R _______________________________________________ mobile-firefox-dev mailing list [email protected] https://mail.mozilla.org/listinfo/mobile-firefox-dev
