Fix timeout/duration calculations using monotonic time and precise tick accumulation

[Copilot]

Description

Two instances incorrectly used .Milliseconds (returns component 0-999) instead of the total duration. For a 2.5 second duration, .Milliseconds returns 500 while .TotalMilliseconds returns 2500.0. Additionally, the timeout calculation used non-monotonic time source (DateTime.UtcNow) which could be affected by system clock adjustments.

Changes

System.Net.Sockets (SocketAsyncContext.Unix.cs:1391, 1414)

• Timeout decrement was subtracting only milliseconds component, causing operations to wait significantly longer than specified when elapsed time exceeded 1 second
• Changed: DateTime waitStart = DateTime.UtcNow; and timeout -= (DateTime.UtcNow - waitStart).Milliseconds;
• To: long waitStart = Stopwatch.GetTimestamp(); and timeout -= (int)Stopwatch.GetElapsedTime(waitStart).TotalMilliseconds;
• Impact: Uses monotonic time source (Stopwatch) instead of DateTime.UtcNow, ensuring timeout calculations are not affected by system clock adjustments (e.g., NTP corrections, manual clock changes)

System.Speech (EngineSite.cs:483, 488, 493)

• Duration accumulation for phoneme events was adding only milliseconds component, producing incorrect totals
• Changed: long totalDuration = 0; with totalDuration += ttsEvent.PhonemeDuration.Milliseconds; and TimeSpan.FromMilliseconds(totalDuration)
• To: long totalDurationTicks = 0; with totalDurationTicks += ttsEvent.PhonemeDuration.Ticks; and TimeSpan.FromTicks(totalDurationTicks)
• Impact: Preserves full TimeSpan precision by accumulating ticks directly instead of converting through floating-point milliseconds, avoiding potential rounding errors

Original prompt

Bug Description

There is a bug in src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs at line 1414:

timeout -= (DateTime.UtcNow - waitStart).Milliseconds;

The code incorrectly uses .Milliseconds instead of .TotalMilliseconds.

The Problem

• .Milliseconds returns only the milliseconds component of the TimeSpan (0-999), not the total elapsed time in milliseconds.
• .TotalMilliseconds returns the entire duration expressed in milliseconds.

Example: If the elapsed time is 2.5 seconds (2500ms total):

• .Milliseconds returns 500 (just the fractional part)
• .TotalMilliseconds returns 2500.0 (the correct total)

This causes the timeout to be decremented by far less than intended when elapsed time exceeds 1 second, making the loop wait much longer than the specified timeout.

Fix Required

1. Fix the occurrence at src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs line 1414:

   timeout -= (int)(DateTime.UtcNow - waitStart).TotalMilliseconds;

2. Search the entire repository for similar patterns where .Milliseconds is used on a TimeSpan when .TotalMilliseconds was likely intended (especially in timeout calculations or elapsed time measurements), and fix any other occurrences found.

Reference

• Source URL: https://github.com/dotnet/runtime/blob/main/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs#L1414

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[Copilot]

Pull request overview

Fixes incorrect timeout/duration calculations caused by using TimeSpan.Milliseconds (component) instead of TimeSpan.TotalMilliseconds (total).

Changes:

• Fix remaining-timeout decrement in SocketAsyncContext.Unix to use total elapsed milliseconds.
• Fix phoneme duration accumulation in System.Speech to use total duration milliseconds.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs	Corrects timeout adjustment logic to subtract total elapsed milliseconds.
src/libraries/System.Speech/src/Internal/Synthesis/EngineSite.cs	Corrects phoneme duration accumulation to account for durations > 1 second.

Comments suppressed due to low confidence (2)

src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs:1414

• There are existing timeout-related functional tests, but none appear to exercise the multi-iteration path in PerformSyncOperation where the remaining timeout is decremented after a wake-up + failed processing. Adding a targeted regression test that forces multiple signals over >1s and asserts the overall operation respects the configured timeout would help prevent this from regressing again.

                    // Adjust timeout and try again.
                    if (timeout > 0)
                    {
                        timeout -= (int)(DateTime.UtcNow - waitStart).TotalMilliseconds;

src/libraries/System.Speech/src/Internal/Synthesis/EngineSite.cs:489

• This change fixes duration accumulation when phoneme conversion spans more than 1 second. Please consider adding a regression test (via the public SpeechSynthesizer PhonemeReached event path) that produces phoneme events with durations crossing a 1s boundary and verifies the resulting converted phoneme event’s duration matches the sum of the originals.

            for (int i = 0; i < _lastComplete;)
            {
                ttsEvent = (TTSEvent)_phonemeQueue.Dequeue();
                totalDuration += (long)ttsEvent.PhonemeDuration.TotalMilliseconds;
                i += ttsEvent.Phoneme.Length;

[stephentoub]

/ba-g unrelated wasm failures