gramps
b37b8a30f9
Measure take ty-1824 on the slice-16 build: the downscale fix worked (conv ~47ms, ring allocs 0) but desktop band was still 88% frozen at 6.8 updates/s. Telemetry isolated the real wall — CreateCopyFromSurfaceAsync readback ~45ms of each conversion, serialized one-in-flight => ~17/s capture cap. Docs fact: pool-sized surfaces CLIP, not scale (Microsoft Learn), so readback stays native; the lever is concurrency. - MaxConcurrentConversions=3 with pool 2->5 buffers (in-flight frames fit) - new MonotonicGate (Interlocked compare-exchange): stale OLDER completions are dropped, never overwrite a newer LatestFrame (mirror of 1742 tear) - FrameRingBuffer.Rent/ConsumeAllocations now lock; downscale row scratch is per-conversion locals - Good Dog test PublishGate_TryPublish_OnlyStrictlyNewerWins; 296/296 green, 0 warnings; docs cited Microsoft screen-capture page + libyuv fixed-point. Local only, no push.
30 lines
1.1 KiB
C#
30 lines
1.1 KiB
C#
using System;
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using System.Threading;
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namespace ytLive.Services;
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/// <summary>
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/// An atomic "publish only if strictly newer" gate for the capture's latest-wins
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/// hand-out. Screen capture conversions may now overlap (slice 17), so two
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/// conversions can finish briefly out of order; without a monotonic gate the slower
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/// (older) completion would overwrite the faster (newer) one's LatestFrame and the
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/// compositor would render STALE content — a time hole in the other direction.
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/// Sequence must be a strictly increasing per-source counter
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/// (<c>Interlocked.Increment</c> in <c>ScreenCaptureFrameSource</c>).
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/// </summary>
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internal sealed class MonotonicGate
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{
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private long _last;
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/// <summary>Returns true iff <paramref name="seq"/> is strictly newer than every
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/// seq accepted so far (and records it).</summary>
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public bool TryPublish(long seq)
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{
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while (true)
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{
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var current = Interlocked.Read(ref _last);
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if (seq <= current) return false;
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if (Interlocked.CompareExchange(ref _last, seq, current) == current) return true;
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}
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}
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} |