[2026-11-03] eagle: work/projects/cpm-project-summary-2026-11-03.md
This commit is contained in:
Alexey Martemyanov committed
1 parent
70e68145b8
commit
68e617a17f
1 file changed
+66
-22
@@ -14,28 +14,46 @@ Goal: permanent stuck reports below 1% of DAU (0.2-0.5% counts as success).
|
||||
|
||||
## What the project has achieved
|
||||
|
||||
- Telemetry that attributes failures (public since Oct/5). We can now see what state the extension was in when a page got no response.
|
||||
- Fixed the deterministic per-tab bugs: tab merging, Close Other Tabs, pinned tabs and window close (macOS).
|
||||
- Reproduced the main failure patterns on real WebKit, with the event sequences matched to production.
|
||||
- Oct/26 release (macOS 1.213 / iOS 7.243): new episode telemetry, recovery for slow wake, error 6 retry and slow startup, restart after a networking process crash.
|
||||
- Nov/2 release (1.214 / 7.244): stable extension origin (P3, only on OS 26.6+), and the fix for browser error pages being counted as CPM failures.
|
||||
- Result so far: the noise is gone, permanent failures are not. On iOS 26.6+, startup-missing and no-view reports are down by over 90% against 7.243 on the same day. Permanent share of DAU is about the same as before.
|
||||
Success criteria: permanent stuck reports below 1% of DAU (0.2-0.5% counts as success). Permanent = no response for 5 minutes, confirmed by a repeat or a reload.
|
||||
|
||||
## Hypotheses and fixes that did not work out
|
||||
Progress against it (1.213 / 7.243 days 1-2 → 1.214 / 7.244 day 1):
|
||||
|
||||
- Deallocation race fix and its A/B test: cancelled because the metrics were too blurry, flag never activated. Data showed no relation to the released fixes.
|
||||
- Slow wake fix (P1): shipped, no measurable effect on the wake group. The background is ready in under 1s, so the loss happens after that.
|
||||
- Hung or crashed background process: not the cause, under 1% of failures show it.
|
||||
- Memory pressure, feature flag toggling, "failed load blocks forever": not reproduced or ruled out as a global cause.
|
||||
- Lost message after wake: could not be reproduced in WebKit tests (0 lost in ~1,500 wakes, also with real pages and the ad blocker running).
|
||||
- Late page reload fix: default off and never fired.
|
||||
- Graveyard mitigation: not supported by the data, not pursued.
|
||||
- iOS: 0.43% → 0.44% of DAU. Inside the target.
|
||||
- macOS: 2.87% → 1.89% of DAU (any failure 28.5% → 15.1%). Target not reached yet. Nov/9 fixes bring it to about 1.6%.
|
||||
|
||||
Breakage measurement, built and corrected:
|
||||
|
||||
- Production telemetry for the stuck extension: one episode report with failure groups, tab scope, repeat count, and rates against DAU. Before it we could not separate stuck from recovered failures or attribute a cause. [Improve telemetry](https://app.asana.com/1/137249556945/task/1219531810004069?focus=true), [TD: failure pixels attribution](https://app.asana.com/1/137249556945/task/1218619301158188?focus=true).
|
||||
- Error pages were reported as breakages on macOS. Fixed, so the macOS figure is now accurate: any failure 28.5% → 15.1%, permanent 2.87% → 1.89% of DAU. [Fix false-positive breakage reports for error pages](https://app.asana.com/1/137249556945/task/1220003778559452?focus=true).
|
||||
|
||||
Breakage fixes shipped, with what each did:
|
||||
|
||||
- Stable extension origin ([P3: stable baseURL fix](https://app.asana.com/1/137249556945/task/1219643764290826?focus=true), [Disable stable baseURL fix for OS<26.6](https://app.asana.com/1/137249556945/task/1220003778559448?focus=true), OS 26.6+): removes a 1.5 to 32 s startup blackout after an origin change. iOS 26.6+ startup-missing and no-view reports down over 90%.
|
||||
- macOS pinned tab lost on window close ([P5: pinned tab after windowDidClose](https://app.asana.com/1/137249556945/task/1219643712648486?focus=true)) and tab merging ([Fix Tab Merging causing CPM failure](https://app.asana.com/1/137249556945/task/1218356681060823?focus=true)): reproduced and fixed. P5 tests 9 pass with fix → 5 expected failures with it off → 27 pass.
|
||||
- Wake and startup recovery ([P1&P2[&P4]: Fix init loss on background unload](https://app.asana.com/1/137249556945/task/1219531810004072?focus=true)): applied to 2,026 iOS / 89 macOS episodes on Oct/26.
|
||||
- Network process restart ([Fix CPM breakage on network process crash](https://app.asana.com/1/137249556945/task/1219531810004073?focus=true)): applied 476 iOS / 277 macOS times on Oct/26.
|
||||
- Public Nov/9: [Restart extension context when error 6 leaves the background view alive](https://app.asana.com/1/137249556945/task/1219939142983214?focus=true) (up to 0.08% DAU iOS) and [Upgrade Web Extensions before loading](https://app.asana.com/1/137249556945/task/1220004977087625?focus=true) (macOS 0.26%, iOS 0.05% DAU).
|
||||
|
||||
Causes proved by reproduction:
|
||||
|
||||
- iOS error-6 loop: stale failed background ([WebExtensions breakage harness](https://app.asana.com/1/137249556945/task/1219531810004071?focus=true)). Fixed by the Nov/9 error 6 restart.
|
||||
- Origin change cleaning the cache before startup (fixed by P3).
|
||||
- macOS P6: a tab without a controller never answers. 0.42% of DAU, no fix yet.
|
||||
|
||||
Hypotheses tested and rejected:
|
||||
|
||||
- [Deallocation race fix](https://app.asana.com/1/137249556945/task/1217907325352233?focus=true), [A/B](https://app.asana.com/1/137249556945/task/1218356681060819?focus=true), [flag activation](https://app.asana.com/1/137249556945/task/1219036128743441?focus=true): flag never activated, data showed no relation.
|
||||
- Hung or crashed background process: under 1% of failures show it.
|
||||
- Lost message after wake: 0 lost in ~1,500 wakes in WebKit tests ([Reproduce the issue](https://app.asana.com/1/137249556945/task/1217907325352231?focus=true)).
|
||||
- [Reload/recover on the Stuck signal](https://app.asana.com/1/137249556945/task/1218744813699968?focus=true): 46% of macOS episodes still got no response after it. Late page reload: 0 fires in production.
|
||||
- Memory pressure, feature flag toggling, "failed load blocks forever": not reproduced.
|
||||
- Graveyard mitigation: not supported by the data.
|
||||
|
||||
## Fixes going public next week (Nov/9)
|
||||
|
||||
- Upgrade-before-load ([#7767](https://github.com/duckduckgo/apple-browsers/pull/7767)): load the new extension version first on launch, instead of an outdated one.
|
||||
- [Upgrade Web Extensions before loading](https://app.asana.com/1/137249556945/task/1220004977087625?focus=true): load the new extension version first on launch, instead of an outdated one.
|
||||
- Expected: removes part of the "extension updated" group (macOS 0.26% DAU, iOS 0.05%). Launch upgrades only, so partial.
|
||||
- Error 6 restart ([#7730](https://github.com/duckduckgo/apple-browsers/pull/7730)): restart the stuck background when the failed view is still retained.
|
||||
- [Restart extension context when error 6 leaves the background view alive](https://app.asana.com/1/137249556945/task/1219939142983214?focus=true): restart the stuck background when the failed view is still retained.
|
||||
- Expected: up to 0.08% DAU on iOS, negligible on macOS. Partial, most error 6 reports only have it in history.
|
||||
- Together: macOS 1.89% to about 1.6%, iOS 0.44% to about 0.3-0.35%. Upper bounds, not measured.
|
||||
|
||||
@@ -44,7 +62,7 @@ Goal: permanent stuck reports below 1% of DAU (0.2-0.5% counts as success).
|
||||
One day, early adopters, macOS has about 9k DAU. Treat as a rough picture.
|
||||
|
||||
- Permanent stuck = no response for 5 minutes, confirmed by a repeat or a reload. Browser-wide = 2+ tabs, one-tab = single tab.
|
||||
- macOS: any failure 15.1% (28.5% on 1.213 days 1-2), permanent 1.89% (2.87% on 1.213 days 1-2, but the mature 1.213 population is also at 1.9%).
|
||||
- macOS: any failure 15.1%, permanent 1.89%. The earlier 28.5% / 2.87% on 1.213 included error pages, so the drop is the metric fix. Mature 1.213 is also at ~1.9%.
|
||||
- Browser-wide 1.22%, one-tab 0.68%.
|
||||
- Idle wake 0.68%, tab not connected (P6) 0.42%, other 0.30%, extension updated 0.26%, recent load 0.19%.
|
||||
- iOS: any failure 8.0%, permanent 0.44% (0.39% on 7.243 days 1-2).
|
||||
@@ -56,8 +74,34 @@ One day, early adopters, macOS has about 9k DAU. Treat as a rough picture.
|
||||
|
||||
## Plan
|
||||
|
||||
- Clean up what did not work: remove the never-activated flags and experiment code (deallocation race, graveyard, late reload), the unused readiness pixels and the old debug pixels. Keep the kill-switch flags on fixes that change behavior until their effect is measured.
|
||||
- Rebuild the metrics as a permanent small set: one episode report with a fixed format, rates against DAU, a sample of healthy navigations as baseline. Drop the tokens and flags that did not help. Publish old and new formats for one release to keep the trend.
|
||||
- Add extension lifecycle metrics to diagnose the wake problem: where the init message stops (page, background, native checks, dashboard update, answer back to the page). Plus a check of the background state when a failure is reported. Needs a privacy review and extension and app releases, so data in 1-2 release cycles.
|
||||
- Mitigations to decide on, not planned yet: retry the init from the page when no answer arrives, and a keep-warm A/B for the background. Both work without knowing the cause.
|
||||
- Open: P6 has no fix, and the wake group will not be solved without the new metrics. If they show nothing actionable, close the project and reset the target.
|
||||
Cleanup, this week:
|
||||
|
||||
- [Feature flags cleanup](https://app.asana.com/1/137249556945/task/1220159402040629?focus=true) (task is empty in Asana, content below). Registry tasks per flag:
|
||||
- Remove the fix and the flag, they did not work or never ran:
|
||||
- [cpmBackgroundGraveyardTreatment](https://app.asana.com/1/137249556945/task/1218860893478440?focus=true): graveyard mitigation, not supported by data.
|
||||
- [cpmLateBackgroundDocumentRecovery](https://app.asana.com/1/137249556945/task/1219588497257482?focus=true): late page reload, default off, 0 fires.
|
||||
- [cpmMessagingHangRecovery](https://app.asana.com/1/137249556945/task/1218855001659655?focus=true): reload on the stuck signal, 46% still no response; decide keep or remove.
|
||||
- [cpmBackgroundLoadRecovery](https://app.asana.com/1/137249556945/task/1219701603183698?focus=true): P1/P2 wake and retry, no measurable effect.
|
||||
- Remove the diagnostics flags together with the diagnostics layer:
|
||||
- [cpmDiagnosticsRecorder](https://app.asana.com/1/137249556945/task/1218785444896174?focus=true): recorder and unresponsive token.
|
||||
- [cpmBackgroundDelegateProxy](https://app.asana.com/1/137249556945/task/1218782530802146?focus=true): delegate proxy for diagnostics.
|
||||
- Keep the fix, remove the failsafe flag once its effect is measured:
|
||||
- [cpmNetworkProcessRecovery](https://app.asana.com/1/137249556945/task/1219701603183695?focus=true): network restart.
|
||||
- [cpmStableBaseURL](https://app.asana.com/1/137249556945/task/1219728649844711?focus=true): stable origin; flag state is not visible in pixels, check the remote config first.
|
||||
- [webExtensionSharedPinnedTabWindowClose](https://app.asana.com/1/137249556945/task/1219660990760563?focus=true): P5.
|
||||
- [webExtensionStateRestorationGate](https://app.asana.com/1/137249556945/task/1218931841045393?focus=true): session restoration race.
|
||||
- [cpmBackgroundLoadRestart](https://app.asana.com/1/137249556945/task/1219970564251181?focus=true): error 6 restart, after Nov/9 data.
|
||||
- [Pixel data cleanup](https://app.asana.com/1/137249556945/task/1220159402040630?focus=true) (task is empty in Asana, content below):
|
||||
- Remove the treatment pixels that only say "applied": background_wake, background_load_retry, install/upgrade readiness, late_document_reload, network_process_recovery_applied, startup_response_missing.
|
||||
- Remove the temporary episode parameters that only served the investigation (bg_events and the other debug fields), after the new metrics are live.
|
||||
|
||||
Metrics, next two weeks:
|
||||
|
||||
- Permanent small set: one episode report with a fixed format, rates against DAU, a sample of healthy navigations as baseline. Old and new formats published together for one release to keep the trend. Added to the health indicators dashboard. Task to create.
|
||||
- Extension lifecycle metrics to diagnose the wake problem: where the init message stops (page, background, native checks, dashboard update, answer back to the page), plus a background state check when a failure is reported. Needs a privacy review and extension and app releases, data in 1-2 release cycles. Task to create.
|
||||
- Data check of the Nov/9 fixes: [Analyze attribution data after stage 3](https://app.asana.com/1/137249556945/task/1220159402040627?focus=true).
|
||||
|
||||
Decide later:
|
||||
|
||||
- Mitigations that do not need the cause: retry the init from the page when no answer arrives, keep-warm A/B for the background.
|
||||
- P6 has no fix. The wake group will not be solved without the new metrics. If they show nothing actionable, close the project and reset the target.
|
||||
Reference in new issue
Block a user