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Steps 1 and 2 of the plan the design review set out, landed and measured on the
device. Step 1 answers the question step 2 depended on; step 2 answers the one the
whole line depended on, and the answer is that the window's shape is wrong.
STEP 1 - CAN AN ANSWER BE LOST IN DELIVERY? NO. ReplyPool now counts what the link
took (PostedReplies) and what it refused (FailedReplies), and a non-OK result is
NAMED instead of swallowed: it checked only BUFFER_TOO_SMALL and let
TRANSPORT_CLOSED vanish with no line and no counter, so "the server never sent it"
and "it was sent and the buffer overwrote it" were the same symptom with opposite
fixes. Measured: posted=4501 failed=0. The twenty-answer gap between the server's
tally and the client's was a sampling difference, not a drop - and the server's
m_answered counts ATTEMPTS (incremented before PostReply), which is why it could
never have settled it.
STEP 2 - DOES A RESIDENCY BUDGET FIX THE WINDOW? NO.
Wire_ResourceCreate now measures how many reply-owning records the client has
emitted since the oldest window entry was pushed (ClientSession::ReplyPostings, a
new clock) and takes the oldest answer back as soon as that approaches the reply
buffer's depth, instead of deferring past the point where the answer can still
exist. On the device:
P12win call=4501 cfg=2 eff=2 pending=2 taken=63 pushed=65 blocked=4435
budget=4451 readfail=8872 posts=54377
kind=frame-op frame=14 wait_replies=9078 by_op=2=9071 wall 27.87 s
budget=4451: it fires on essentially EVERY create, the window stops deferring
(pushed=65), and the drain still reads nothing back. THE REASON IS STRUCTURAL, not
a constant:
* the window only gets control WHEN A CREATE ARRIVES. Between two creates this
client emits on the order of a thousand records - at the FIRST failed read the
reply ring already spanned [1175..1504] while the head was seq 310 - and nothing
looks at the window in that gap;
* what displaces a deferred answer is not what this client emits, it is WHAT THE
SERVER ANSWERS. The server is the one behind (one answer per ~5 ms wakeup while
the client runs ahead), so the replies arriving during the gap are its LATE
ANSWERS TO THE EARLIER CREATES - they fill the 8 slots first;
* so the check fires too late by construction. Tightening it does not fix that; it
only removes the deferral entirely, which is what pushed=65 is.
WHAT THAT LEAVES. A deferral is readable only if the client KEEPS the answers it
deferred. The buffer is bounded by COUNT and the client cannot bound how many
answers the server will post between two of its creates, so hoping the buffer still
holds one is a race the client loses - which is also why the earlier two diagnoses
(reply-pool churn, then FIFO-with-no-way-out) were both describing symptoms of the
same thing. The shape that can work is retention: the reader keeps the answers for
the seqs still outstanding (a handful), drops them when read, and reports a LOSS
when a read asks for one it no longer has. That is a transport change - StreamLink's
ring becomes a retention map with a cap and a lost counter - and it is the next step.
BOTH STEPS STAY: step 1 is a net gain on its own, and step 2 is the safe direction
(it can only degrade the window to no-deferral, i.e. the pre-window shape) and its
clock is the one the retention design needs. MOBILEGL_IPC_CREATE_WINDOW stays at 1.
172/172 and 13/13 after the probes were removed. The measurements and the revised
conclusion are in notes/p12/CREATE-WINDOW-MEASURED.md section 9.
MGPipe：MobileGL 前后端拆分
做什么：在 MobileGL 的前端（处理应用的 GL 调用）和后端（调用 GLES / Vulkan 驱动）之间立一份显式接口——前端把状态变化推给后端，后端不再直接读前端的内存。有了这份接口，前后端可以放在两个线程、两个进程，甚至两台机器上运行。
做到哪了（2026-09-25）：接口与拆分已完成到"两个进程、可经 TCP 跨机"。当前在做 P12：让 Android 上的 server 自己开窗口，把画面直接显示到屏幕上——审查后的主机定向测试和 Redmi 真机七项复测已通过；FCL 与跨机 TCP 两项验收仍未完成。→ CURRENT_STAGE_PROGRESS.md
一张图
应用的 GL 调用
→ 前端 MG_Impl：处理 GL 语义；在每条"做事的命令"（draw、clear…）之前，把状态变化整理成记录
→ MGPipe 接口（两张函数指针表，由调用目录 PipeCalls.def 生成）
→ 三选一：直接调用（单线程）│ 队列 → 另一个线程 │ 队列 → 另一个进程 / 另一台机器
→ 后端 MG_Backend：Espryt（GLES）/ Magma（Vulkan），按记录更新自己的状态并调用驱动
← 反向消息（错误、GPU 写回、窗口尺寸）按顺序回到前端
文档导航
| 想知道 | 看 |
|---|---|
| 现在做到哪、下一步 | CURRENT_STAGE_PROGRESS.md |
| 设计要点与各部分设计 | ARCHITECTURE.md → design/ |
| 分几个阶段、每个阶段做了什么 | ROADMAP.md → notes/<阶段>/ |
| 性能与验证的关键数字 | MEASUREMENTS.md |
| 怎么构建、运行、测试 | guide/build-and-run.md |
| 代码在哪 / 术语 / 工程纪律 | guide/code-map.md、guide/glossary.md、guide/discipline.md |
| 各阶段的原始计划、裁定、报告、证据 | notes/ |
整理记录：2026-09-24 两次整理——顶层只留索引，设计正文拆到 design/，上手与参考放 guide/，阶段细节放 notes/<阶段>/；整理前的版本见提交 1fb18d9。更早的设计竞赛与评审稿在 git 历史（8b31de2f、1794ac94、8349babe、87ee17c6）。