主题： performance

• 生产环境中的持续性能剖析：常开的采样剖析能回答什么问题

  持续性能剖析（continuous profiling）会系统性地随时间采集 CPU 和内存剖析数据，并以带标签的序列形式存储，这样团队就能查询昨天整个集群中哪个函数消耗的 CPU 最多、或两个版本之间发生了什么变化之类的问题；采样式剖析器的开销足够低，可以一直保持开启，而 Go 的 /debug/pprof/ 之类的运行时端点或 eBPF 代理则负责提供这些剖析数据。

  article · zh · reviewed · 知识截至 2026-09-16

• Summarizing time in system calls with strace -c, its overhead, and perf trace as an alternative

  strace -c counts time, calls and errors per system call instead of printing every call, but strace's own manual warns that a traced process runs more slowly than an untraced one; perf trace, described as a strace-inspired tool built on perf_events rather than ptrace, is the lower-ceremony alternative when that overhead matters.

  methodology · en · reviewed · 知识截至 2026-09-24

• 变更基准测试：预热、重复次数、离散程度与应报告的内容

  计时对比只有经得起噪声考验才算得上结果：固定工作负载、丢弃预热运行、将各变体的多次重复交替执行、在查看数据前先确定要用的统计量，并在每个数字旁报告离散程度与环境信息。小于运行间离散程度的差异算不上发现。

  methodology · zh · reviewed · 知识截至 2026-09-15

• A first look at Solaris performance: prstat, vmstat, mpstat, iostat and zpool iostat

  prstat -a/-Z, vmstat, mpstat, iostat -xnz and zpool iostat are five read-only commands that cover most first-look performance questions on Solaris 11.4, with zone-aware and disk-latency detail that the similarly-named Linux tools present differently.

  article · en · reviewed · 知识截至 2026-09-24

• 使用 USE 方法查找性能瓶颈

  对 CPU、内存、磁盘、网络、锁等每种资源，检查利用率、饱和度和错误。USE 方法是一份检查清单，能快速发现瓶颈，无需先在应用层凭直觉猜测。

  methodology · zh · reviewed · 知识截至 2026-09-15

• 响应压缩：在哪一层做，排除哪些内容

  在代理或应用中压缩文本响应（HTML、JSON、Markdown），跳过已压缩和流式内容，确保不同编码下的 ETag 如实对应表示，并设置 Vary: Accept-Encoding。

  article · zh · reviewed · 知识截至 2026-09-15

• How much of an agent's context is tool output in real runs, and does trimming it change task success?

  Open question: the MCP specification says clients should validate tool results before passing them to the model but leaves the amount to the client; in recorded agent runs, what share of tokens is tool output rather than instructions or reasoning, and does truncating, summarising or filtering tool output change task success, cost and latency?

  question · en · reviewed · 知识截至 2026-09-16

• 使用 srcset、sizes 和 picture 实现响应式图片

  带宽度描述符的 srcset 配合 sizes 属性，可以让浏览器根据当前视口和像素密度，选择能填满显示区域的最小图片文件。x 描述符为固定显示尺寸提供多种密度；带 source 元素的 picture 用于构图调整和格式回退。始终保留 width 和 height，避免图片加载时布局偏移。

  article · zh · reviewed · 知识截至 2026-09-16

• Sampling Windows Server performance counters with Get-Counter and exporting them to CSV

  Get-Counter samples named counter paths at a chosen interval, continuously or for a fixed count; Export-Counter (Windows PowerShell 5.1 only) preserves every field in the native BLG format, and relog converts a capture to CSV afterwards even without the original Export-Counter command.

  methodology · en · reviewed · 知识截至 2026-09-24

• 生成、评议、修订：自我验证循环何时值得投入

  当评议有外部信号（测试、验证器或来源）和固定评价标准时，让模型评议并修订自身输出的循环能改善结果；缺少这种依据时，已发表的研究结果表明它可能使答案变差。每轮至少增加两次调用，且两次调用的输入量都会随草稿增长。

  article · zh · reviewed · 知识截至 2026-09-16

• VACUUM、autovacuum 与表膨胀

  PostgreSQL 的 MVCC 在更新和删除后会留下失效的行版本；VACUUM 回收这些版本，维护统计信息，并防止事务 ID 回卷。应保持 autovacuum 启用，并针对繁忙表进行调优。

  article · zh · reviewed · 知识截至 2026-09-15

• Web 字体加载：font-display、预加载、unicode-range 子集与度量匹配的后备字体

  首次绘制就显示文字，并让品牌字体加载后不引发布局跳动：用 unicode-range 划分字体子集，只下载用到的文字系统；按角色选择 font-display（正文用 optional，标题用 swap）；用 crossorigin 预加载首次绘制文件；声明带 size-adjust 及 ascent/descent 覆盖值的后备字体，使替换前后换行一致。

  methodology · zh · reviewed · 知识截至 2026-09-16

• ES module builds with declared side effects shrink consumer bundles more than CommonJS builds

  Hypothesis: for a library of many independent functions, a consumer that imports a few of them gets a smaller bundle when the library ships ES modules with a sideEffects declaration than when it ships CommonJS, because tree shaking depends on static import/export structure; a fixture-based comparison is proposed.

  hypothesis · en · reviewed · 知识截至 2026-09-15

• asyncio 何时有用，何时无益

  asyncio 通过在 await 处挂起任务，在单个线程上运行大量受 I/O 限制的任务。它不会加速受 CPU 限制的代码，而协程中的阻塞调用会让整个事件循环停滞。

  article · zh · reviewed · 知识截至 2026-09-15

• Web Vitals：LCP、INP 和 CLS 分别测量什么

  Core Web Vitals 是三个真实用户指标：Largest Contentful Paint（最大可见元素的渲染时间，目标 2.5 秒）、Interaction to Next Paint（最长交互延迟，目标 200 毫秒）和 Cumulative Layout Shift（意外位移，目标 0.1）。每项都按页面加载的第 75 百分位评估。

  article · zh · reviewed · 知识截至 2026-09-15

• When does client-side routing still pay off now that browsers offer bfcache, prerendering and cross-document view transitions?

  Open question: in-page routers were adopted to avoid full page loads, at the cost of shell serving, 404 handling, scroll and focus restoration and a bundle that must arrive first; the back/forward cache, the Speculation Rules API and cross-document view transitions now address the original motivations in multi-page sites. For which sites and interaction patterns does an in-page router still measurably win?

  question · en · reviewed · 知识截至 2026-09-16

• 使用 tracemalloc 快照查找内存泄漏

  尽早通过 PYTHONTRACEMALLOC 或 tracemalloc.start(nframe) 开始跟踪，在预热后和 N 次迭代后各取一份快照，过滤导入噪声，再用 compare_to(..., 'lineno') 找出内存大小随 N 成比例增长的代码行；切换到 'traceback' 分组即可查看调用者。

  methodology · zh · reviewed · 知识截至 2026-09-15

• Performance diagnosis from the macOS Terminal: top, vm_stat, memory_pressure, fs_usage, and powermetrics

  macOS ships BSD-heritage and Apple-specific tools that overlap with what top/vmstat/iostat/strace do on Linux, under different names, units and privilege requirements: top -o cpu, vm_stat, memory_pressure, iostat, fs_usage, powermetrics, and sample <pid>.

  article · en · reviewed · 知识截至 2026-09-24

• Per-process CPU and I/O with pidstat and /proc/<pid>/io: finding what causes I/O wait

  pidstat reports per-task CPU, memory and disk I/O without grepping a name out of top; reading /proc/<pid>/io directly separates logical I/O (rchar/wchar, including cache) from the physical read_bytes/write_bytes that actually reach the device.

  methodology · en · reviewed · 知识截至 2026-09-24

• 为 Python 工作负载选择线程、进程或 asyncio

  先判断热点路径的性质：等待 I/O 适合 asyncio（大量连接、异步库）或线程池（少量阻塞调用）；纯 Python 的 CPU 工作需要进程或自由线程构建；释放 GIL 的原生代码可使用线程。限制每个池的规模，显式选择进程启动方式，并编写关闭流程。

  methodology · zh · reviewed · 知识截至 2026-09-15

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机器可读： JSON