Add feature flag to throttle custom user timings [chromium/src : main]
Michal Mocny (Gerrit)
Michal Mocny added 1 comment![]( "Open in Gerrit")
Drive by comment: Thanks for creating a page_load specific features common file! Good idea.
Question about the motivations here: do we have some known insights that this is slow? I did notice that the way we send these seemed potentially quite verbose, especially as we increase the adoption of custom user timings...
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- Keita Suzuki
- Shunya Shishido
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Shunya Shishido (Gerrit)
Shunya Shishido added 1 comment![]( "Open in Gerrit")
Drive by comment: Thanks for creating a page_load specific features common file! Good idea.
Question about the motivations here: do we have some known insights that this is slow? I did notice that the way we send these seemed potentially quite verbose, especially as we increase the adoption of custom user timings...
We don't recognize known regressions so far. But we'd like to restrict it because currently it's sent to from the renderer to the browser immediately using a dedicated Mojo call[1] while other events (including "regular" user timings e.g. mark_fully_visible, mark_interactive) are sent via timer[2].
This exceptional IPC was introduced to understand abandoned navigation timing precisely, and we were aware that important loading milestones were sent via performance.mark() in some specific websites.
We don't actively monitor navigation abandoned timings in UMA anymore. And recently we received a request to record performance.mark() events triggered in subframes (currently we restrict it on the main frame only) crbug.com/467177770.
As this was an exceptional approach, we'd like to handle custom user timings as same as other events in PLMO before accepting events from subframes not to increase the number of IPCs,
[1] https://source.chromium.org/chromium/chromium/src/+/main:components/page_load_metrics/renderer/page_timing_metrics_sender.cc;l=300-307;drc=f5cd0240d3fb3c70b16d09a992c43a43586001b4
[2] https://source.chromium.org/chromium/chromium/src/+/main:components/page_load_metrics/renderer/page_timing_metrics_sender.cc;l=322-345;drc=6d3e2ca997ca3ef995f719b22a1658a250a22d1e
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- Michal Mocny
- Takashi Toyoshima
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Takashi Toyoshima (Gerrit)
Takashi Toyoshima voted Code-Review+1![]( "Open in Gerrit")
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Shunya Shishido (Gerrit)
Shunya Shishido voted Commit-Queue+2![]( "Open in Gerrit")
| Commit-Queue | +2 |
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Keita Suzuki (Gerrit)
Keita Suzuki voted Code-Review+1![]( "Open in Gerrit")
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Chromium LUCI CQ (Gerrit)
Chromium LUCI CQ submitted the change![]( "Open in Gerrit")
Change information
Add feature flag to throttle custom user timings
Introduce the kThrottleSendingCustomUserTimings feature flag to control
whether custom user timings are throttled when sent from the renderer to
the browser process.
This feature is disabled by default. The flag is defined in the
components/page_load_metrics/common directory to ensure accessibility
for both browser and renderer classes.
- M components/page_load_metrics/common/BUILD.gn
- A components/page_load_metrics/common/features.cc
- A components/page_load_metrics/common/features.h
Code-Review: +1 by Keita Suzuki, +1 by Takashi Toyoshima
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