Performance/Metrics

This page documents metrics from Performance Team services. Currently in Graphite.

Deployment and monitoring

See Performance/Runbook/Webperf services for the internal details of these services, such as where the metrics originate, and how they are processed/aggregated.

navtiming-2 metrics

The navtiming-2 metrics are available in Graphite under the frontend.navtiming2 prefix.

Difference with navtiming-1

Notable differences:

• Offsets are computed relative to fetchStart instead of navigationStart.
• We no longer filter out zero values.
• The sanity filter no longer has an upper bound.
• When the sanity filter encounters negative numbers, it rejects the entire event instead of just the individual data point.

See phab:T104902 for more information about why the metrics were redefined.

Offsets

• responseStart: From PerformanceTiming, relative to fetchStart.
• firstPaint: (non-standard)
• domInteractive: From PerformanceTiming, relative to fetchStart.
• domComplete: From PerformanceTiming, relative to fetchStart.
• loadEventStart: From PerformanceTiming, relative to fetchStart.
• loadEventEnd: From PerformanceTiming, relative to fetchStart. Also known as "Page load end" or "Total page load time". This typically corresponds with the browser's native page loading indicator.

Deltas

• dns: Computed client-side from PerformanceTiming domainLookupEnd - domainLookupStart. (Transmitted as "dnsLookup")
• unload: Computed client-side from PerformanceTiming unloadEventEnd - unloadEventStart.
• redirect: Computed client-side from PerformanceTiming redirectEnd - redirectStart. (Transmitted as "redirecting").
• mediaWikiLoad: Computed client-side based on custom mwLoadEnd and mwLoadStart measures. (Transmitted as "mediaWikiLoadComplete").
• tcp: Computed server-side as connectEnd - connectStart. This includes SSL negotiation.
• request: Computed server-side as responseStart - requestStart.
• response: Computed server-side as responseEnd - responseStart.
• processing: Computed server-side as domComplete - responseEnd.
• onLoad: Computed server-side as loadEventEnd - loadEventStart.
• ssl: Computed server-side as connectEnd - secureConnectionStart. This is a subset of tcp.

SaveTiming metrics

SaveTiming get reported to mw.performance.save in statsd. To see if it's running properly, the mw.performance.save.sample_rate key should have hits.

• View Grafana dashboard
• View Coal dashboard

See also

• Performance
• performance.wikimedia.org