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diff --git a/chromium/base/task/thread_pool/historical_histogram_data.md b/chromium/base/task/thread_pool/historical_histogram_data.md new file mode 100644 index 00000000000..d253731b6fb --- /dev/null +++ b/chromium/base/task/thread_pool/historical_histogram_data.md @@ -0,0 +1,92 @@ +# Historical Histogram Data + +This page presents data captured from `base::ThreadPool` histograms at a given +point in time so it can be used in future design decisions. + +All data is 28-day aggregation on Stable channel. + +## Number of tasks between waits + +Number of tasks between two waits by a foreground worker thread in a +browser/renderer process. + +Histogram name: ThreadPool.NumTasksBetweenWaits.(Browser/Renderer).Foreground +Date: August 2019 +Values in tables below are percentiles. + +### Windows + +| Number of tasks | Browser process | Renderer process | +|-----------------|-----------------|------------------| +| 1 | 87 | 92 | +| 2 | 95 | 98 | +| 5 | 99 | 100 | + +### Mac + +| Number of tasks | Browser process | Renderer process | +|-----------------|-----------------|------------------| +| 1 | 81 | 90 | +| 2 | 92 | 97 | +| 5 | 98 | 100 | + +### Android + +| Number of tasks | Browser process | Renderer process | +|-----------------|-----------------|------------------| +| 1 | 92 | 96 | +| 2 | 97 | 98 | +| 5 | 99 | 100 | + + +## Number of tasks run while queueing + +Number of tasks run by ThreadPool while task was queuing (from time task was +posted until time it was run). Recorded for dummy heartbeat tasks in the +*browser* process. The heartbeat recording avoids dependencies between this +report and other work in the system. + +Histogram name: ThreadPool.NumTasksRunWhileQueuing.Browser.* +Date: September 2019 +Values in tables below are percentiles. + +Note: In *renderer* processes, on all platforms/priorities, 0 tasks are run +while queuing at 99.5th percentile. + +### Windows + +| Number of tasks | USER_BLOCKING | USER_VISIBLE | BEST_EFFORT | +|-----------------|---------------|--------------|-------------| +| 0 | 95 | 93 | 90 | +| 1 | 98 | 95 | 92 | +| 2 | 99 | 96 | 93 | +| 5 | 100 | 98 | 95 | + +### Mac + +| Number of tasks | USER_BLOCKING | USER_VISIBLE | BEST_EFFORT | +|-----------------|---------------|--------------|-------------| +| 0 | 100 | 100 | 99 | +| 1 | 100 | 100 | 99 | +| 2 | 100 | 100 | 99 | +| 5 | 100 | 100 | 100 | + +### Android + +| Number of tasks | USER_BLOCKING | USER_VISIBLE | BEST_EFFORT | +|-----------------|---------------|--------------|-------------| +| 0 | 99 | 98 | 97 | +| 1 | 100 | 99 | 99 | +| 2 | 100 | 99 | 99 | +| 5 | 100 | 100 | 100 | + +### Chrome OS + +For all priorities, 0 tasks are run while queueing at 99.5th percentile. + +### Analysis + +The number of tasks that run while a BEST_EFFORT task is queued is unexpectedly +low. We should explore creating threads less aggressively, at the expense of +keeping BEST_EFFORT tasks in the queue for a longer time. See +[Bug 906079](https://crbug.com/906079). |