kenoss@chromium.org taiyo@chromium.org chrome-loading@chromium.org

When a navigation started, `PrefetchMatchResolver` collects potentially matching prefetches for it. Judging a prefetch actually matches or not needs non-redirect header. If a prefetch has non-redirect header and actually matched, then this process ends synchronously. If not, it waits non-redirect headers until it finds a matched and servable one or there is no more candidates. This histogram records that duration navigation was blocked by the prefetch matching, when the matching is settled. Zero is recorded when the navigation is not blocked. This histogram is recorded per potentially matching candidate, with its TriggerType and Eagerness as {TriggerTypeAndEagerness}, and whether its candidate was eventually served or not as {WasServed}. Recorded iff {PrerenderOrNonPrerender}.

kenoss@chromium.org taiyo@chromium.org chrome-loading@chromium.org

yoichio@chromium.org taiyo@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchContainer` is added to `PrefetchService` to when the domain lookup for the corresponding URL request is started. This metric is recorded when `PrefetchContainer::dtor()` is called if it received a non-redirect header and domain lookup was performed. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

kenoss@chromium.org chrome-loading@chromium.org

Records duration from when `PrefetchContainer` is added to `PrefetchService` to when `PrefetchContainer` received non-redirect header. This metrics is recorded when `PrefetchContainer::dtor()` is called if it received non-redirect header. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

kenoss@chromium.org chrome-loading@chromium.org

Records duration from when `PrefetchContainer` is added to `PrefetchService` to when `PrefetchContainer` received initial eligibility. This metrics is recorded when `PrefetchContainer::dtor()` is called if it passed initial eligibility check. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

kenoss@chromium.org chrome-loading@chromium.org

Records duration from when `PrefetchContainer` is added to `PrefetchService` to when `PrefetchContainer` finished load successfully. This metrics is recorded when `PrefetchContainer::dtor()` is called if it completed the load successfully. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

kenoss@chromium.org chrome-loading@chromium.org

Records duration from when `PrefetchContainer` is added to `PrefetchService` to when `PrefetchService` starts its loading process (i.e., `PrefetchService::StartSinglePrefetch` is called). This metrics is recorded when `PrefetchContainer::dtor()` is called if it started the load. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

taiyo@chromium.org kenoss@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchContainer` is added to `PrefetchService` to when its URLRequest is started in //net layer (i.e., when `URLRequest::Start()` is called). This metrics is recorded when `PrefetchContainer::dtor()` is called if it received a non-redirect header. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

hayato@chromium.org chrome-loading@chromium.org

Records the time taken to call http network transaction connected callback. This metrics is recorded when `PrefetchContainer::dtor()` is called if it started the load. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

hayato@chromium.org chrome-loading@chromium.org

Records the time taken for HTTP stream creation to finish. This metrics is recorded when `PrefetchContainer::dtor()` is called if it started the load. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

taiyo@chromium.org kenoss@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchContainer` receives initial eligibility` to when `PrefetchService` starts its loading process (i.e., `PrefetchService::StartSinglePrefetch` is called), which typically represents the duration the prefetch waits on the scheduler's queue. This metrics is recorded when `PrefetchContainer::dtor()` is called if it started the load. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

hayato@chromium.org chrome-loading@chromium.org

Records the time taken for HTTP stream initialization to finish if the initialization was blocked, otherwise zero. This metrics is recorded when `PrefetchContainer::dtor()` is called if it started the load. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

wbjacksonjr@chromium.org taiyo@chromium.org chrome-loading@chromium.org

Records the time delta between a missed prefetch matching and a subsequent prefetch for the same resource. This is logged when a prefetch request is sent to the network for a URL that was recently navigated to by the user and that could have been served by the prefetch if it had been available. A smaller time delta indicates a potential race condition between the navigation and the prefetch. This metric is logged in milliseconds and is only recorded against the latest navigation that could've matched with the prefetch. Note that this is calculated from non-SW-controlled `PrefetchMatchResolver` i.e. it is calculated for each redirect, and it ignores SW-controlled `PrefetchMatchResolver` case. Also, this information of being unmatched is stored in an LRU with a limited size, so older mismatches might not be taken into account. Please see `PrefetchService::recent_unmatched_navigated_keys_for_metrics_` for more details. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

yoichio@chromium.org taiyo@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchService` starts its loading process (i.e., `PrefetchService::StartSinglePrefetch` is called) to when the domain lookup for the corresponding URL request is started. This metric is recorded when `PrefetchContainer::dtor()` is called if it received a non-redirect header and domain lookup was performed. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

taiyo@chromium.org kenoss@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchService` starts its loading process (i.e., `PrefetchService::StartSinglePrefetch` is called) to when `PrefetchContainer` received non-redirect header. This metrics is recorded when `PrefetchContainer::dtor()` is called if it received non-redirect header. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

taiyo@chromium.org kenoss@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchService` starts its loading process (i.e., `PrefetchService::StartSinglePrefetch` is called) to when `PrefetchContainer` finished load successfully. This metrics is recorded when `PrefetchContainer::dtor()` is called if it completed the load successfully. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

taiyo@chromium.org kenoss@chromium.org chrome-loading@chromium.org

Records the duration from when `PrefetchService` starts its loading process (i.e., `PrefetchService::StartSinglePrefetch` is called) to when its URLRequest is started in //net layer (i.e., when `URLRequest::Start()` is called). This metrics is recorded when `PrefetchContainer::dtor()` is called if it received a non-redirect header. This histogram is only recorded for prefetches of {TriggerTypeAndEagerness}.

taiyo@chromium.org chrome-loading@chromium.org

This histogram records how many times the `PrefetchContainer` has been served to the navigation. The count is incremented when `PrefetchContainer` receives the `PrefetchMatchResolver`'s notification that the container is serevd (i.e. `PrefetchMatchResolver::UnregisterCandidate`), and its value is recorded on `PrefetchContainer::dtor()`. This histogram is recorded with its TriggerType and Eagerness as {TriggerTypeAndEagerness}.

kouhei@chromium.org kenoss@chromium.org taiyo@chromium.org chrome-loading@chromium.org

When a navigation started, `PrefetchMatchResolver` collects potentially matching prefetches for it. Judging a prefetch actually matches or not needs non-redirect header. If a prefetch has non-redirect header and actually matched, then this process ends synchronously. If not, it waits non-redirect headers until it finds a matched and servable one or there is no more candidates. This histogram records whether this process ends synchronously (i.e. whether prefetch matching blocked the navigation), when the above prefetch matching is settled. This histogram is recorded per potentially matching candidates, with its TriggerType and Eagerness as {TriggerTypeAndEagerness}. Recorded iff {PrerenderOrNonPrerender}.

kouhei@chromium.org kenoss@chromium.org taiyo@chromium.org chrome-loading@chromium.org

When a navigation started, `PrefetchMatchResolver` collects potentially matching prefetches for it. Judging a prefetch actually matches or not needs non-redirect header. If a prefetch has non-redirect header and actually matched, then this process ends synchronously. If not, it waits non-redirect headers until it finds a matched and servable one or there is no more candidates. This histogram records whether this process ends synchronously (i.e. whether prefetch matching blocked the navigation), when the above prefetch matching is settled. This histogram is recorded per potentially matching candidates, with its TriggerType and Eagerness as {TriggerTypeAndEagerness}. Before 2025-04-25, this histogram was recorded as `PrefetchProxy.AfterClick.PrefetchMatchingBlockedNavigationWithPrefetch.*`

kenoss@chromium.org chrome-prerendering@google.com

Records `PrefetchPotentialCandidateCollectResult` when a prerender that triggered prefetch ahead of prerender, tried to use prefetch but there is no prefetch candidate in `PrefetchMatchResolver`.

kenoss@chromium.org chrome-prerendering@google.com

The combination of `PrefetchPotentialCandidateServingResult`, `PrefetchServableState`, and `PrefetchMatchResolverAction`. See `GetCodeOfPotentialCandidateServingResultAndServableStateAndMatcherAction()` for the details of the value. How to decode: prompt: " Generate a python program that decodes `GetCodeOfPotentialCandidateServingResultAndServableStateAndMatcherAction()`. Example: ``` $ decode.py 124181 ('PrefetchPotentialCandidateServingResult::kNotServedLoadFailed', 'PrefetchServableState::kNotServable', 'PrefetchMatchResolverAction::ActionKind::kDrop', 'PrefetchContainer::LoadState::kFailedDeterminedHead', None) ``` " Recorded when prefetch matching received unmatch in `PrefetchMatchResolver::OnDeterminedHead()`.

taiyo@chromium.org chrome-loading@chromium.org

When a navigation started, `PrefetchMatchResolver` collects potentially matching prefetches for it. Judging a prefetch actually matches or not needs non-redirect header. If a prefetch has non-redirect header and actually matched, then this judging ends synchronously. If not, it being the `PrefetchMatchResolver` waits for non-redirect headers until it finds a matched and servable one or there is no more candidates. This histogram records the result of the serving judgement per those potentially matching candidates. Recorded when that serving judgement is settled and the candidate is unregistered from the resolver (i.e. `PrefetchMatchResolver::UnregisterCandidate`). This histogram is recorded per potentially matching candidate, with its TriggerType and Eagerness as {TriggerTypeAndEagerness}.

taiyo@chromium.org hiroshige@chromium.org

Records if there are any mismatched headers in {ValidateResourceRequestHeaders} in ValidateResourceRequestForPrePrefetch. Logged for every PrePrefetch-initiated prefetch {ValidateResourceRequestMode}.

taiyo@chromium.org hiroshige@chromium.org

Records the header name of every mismatched header in {ValidateResourceRequestHeaders} in ValidateResourceRequestForPrePrefetch. Logged for every mismatched header for every PrePrefetch-initiated prefetches {ValidateResourceRequestMode}.