Tag

latency

35 articles

Oct 12, 2026 Bus Matrix Arbitration and What DMA Contention Costs the Core How a multi-master bus fabric picks a winner when the core and a DMA engine target the same SRAM, why round-robin is not always fair, and how contention shows up as jitter. embedded systems
Aug 22, 2026 Temporal Coupling Between Services What a synchronous call forces on two services, how message passing changes the coupling without removing it, and where each style breaks under load. software architecture
Aug 22, 2026 Utilization and the Nonlinear Growth of Waiting Time Why queue delay rises faster than load, how the shape of the curve depends on service-time variability rather than on arrival statistics, and why a utilization target is a statement about tail risk. performance engineering
Jun 11, 2026 Choosing an I/O Scheduler and Setting Queue Depth What an elevator can still do on a device with no seek cost, the difference between the none, mq-deadline, and Kyber schedulers, and how queue depth controls latency. filesystems
May 21, 2026 Utilization Targets and the Knee of the Latency Curve Why latency stays flat until utilization approaches one and then rises sharply, how arrival variability moves the knee, and how to locate the operating point from measurements rather than doctrine. performance engineering
May 8, 2026 Bandwidth-Bound and Latency-Bound Work How to tell which of the two memory limits a kernel is actually hitting, why the remedy differs completely, and how the arithmetic intensity decides. performance engineering
Apr 29, 2026 Why Queueing Delay Rises Sharply Near Link Utilization How the shape of the M/M/1 waiting-time curve explains the knee in latency-versus-load graphs, and why utilisation targets are set where they are. networking
Apr 9, 2026 Incremental Rehashing: Spreading a Resize Across Operations How two tables and a migration cursor turn an O(n) resize pause into constant work per operation, and what lookups must do while both tables are live. data structures
Feb 17, 2026 Steal Time and vCPU Skew: What Happens When a Guest Gets Fewer Cores Than It Asked For Why a guest cannot see its own descheduling, how paravirtualized steal accounting reports it, and why lock holders that lose the CPU cost far more than the time they lost. virtualization
Feb 7, 2026 Off-CPU Time and Scheduler Delay as a Profile How to attribute the time a thread spends not running, why the stack at the moment of blocking is the right attribution, and what makes off-CPU data heavy-tailed. observability
Jan 28, 2026 Concurrency Limits Derived from Little's Law How the relation between in-flight requests, arrival rate, and latency produces a concurrency limit, and why an adaptive limit tracks a dependency that changes speed. backend systems
Nov 24, 2025 Measuring Latency Under Load Without Fooling Yourself How to design a delay measurement that separates fixed path delay from queueing, which load patterns expose bufferbloat, and why idle-path numbers mislead. networking
Nov 10, 2025 Queue Time, Service Time, and What a Timeout Measures A client-side timeout covers every wait in the path, including queues the client never sees, and that decomposition explains why a server can look fast while its callers time out. backend systems
Aug 5, 2025 Radio Resource Control States and the Tail Timer After the Last Byte Why a cellular radio stays powered for seconds after a transfer ends, what each connection state costs, and how the spacing of requests decides which transitions are paid. mobile computing
Jun 23, 2025 Deferred Interrupt Work: Splitting Handlers from Processing Why the top half of a handler should only acknowledge and wake, how the bottom half runs at a chosen priority, and what the split costs in latency. embedded systems
Apr 13, 2025 Splitting Prefill From Decode Inside a Step Prompt processing is compute-bound and token generation is bandwidth-bound; how mixing them in one step costs latency, and how chunked prefill bounds the interference. inference systems
Feb 24, 2025 Timer Wheels and the Cost of Finding the Next Expiry Why a sorted list or a heap is the wrong structure for thousands of concurrent timers, how a hashed wheel amortises the work, and what the resolution trade costs. operating systems
Jan 27, 2025 Quorum Placement and the Latency of the Second-Fastest Replica How the geometry of replica placement decides commit latency for majority quorums, and why adding a distant replica to a three-node group can be free or fatal. cloud infrastructure
Dec 30, 2024 The Inter-Region Latency Floor Set by Fiber Paths Why the minimum round-trip time between two regions is fixed by geography and glass rather than by provisioning, and how to compute that floor before choosing a topology. cloud infrastructure
Dec 25, 2024 Throughput, Latency, and Why Concurrency Is Not Parallelism How the relation between completion rate, response time, and in-flight work constrains every scaling decision, and why overlapping waits and splitting computation buy throughput in different ways. performance engineering
Nov 29, 2024 Timer Clamping, Background Throttling, and Cooperative Yielding The integer arithmetic and nesting rules behind setTimeout, why intervals do not catch up, and how scheduler priority levels change when a callback runs. web platform
Sep 9, 2024 The Memory Gap and the Arithmetic of Average Access Time How the latency of each level combines into one average, why a small miss rate can dominate the total time, and where the model stops describing real hardware. memory systems
Sep 2, 2024 Where Latency Is Measured, and Why Percentiles Do Not Average A serving latency number is a function of the point where the clock starts, and percentiles computed at different layers cannot be combined; both facts determine whether a monitoring figure means anything. inference systems
Aug 12, 2024 Standing Queues and the Buffer Sizing Trade-Off Why deep buffers turn into permanent added latency, how the bufferbloat diagnosis differs from ordinary congestion, and what the bandwidth-delay product says about how much buffer is needed. networking
Jun 27, 2024 Deriving Latency Targets from Percentile Distributions Why a percentile objective is really a tail-count budget, how bucket layout limits the achievable precision, and what a latency target costs in headroom. observability
Jun 24, 2024 Yield Points and What Makes a Task Cooperatively Schedulable Why a scheduler that cannot interrupt needs the compiler to place checkpoints, how the choice of checkpoint changes latency, and what a missing yield point does to every task behind it. language runtimes
Jun 22, 2024 Retiming, Pipelining, and Register Balancing in the Fabric How moving registers across combinational logic changes which resources a path traverses, why the fabric makes retiming cheaper than in an ASIC, and where the technique stops helping. hardware engineering
Mar 14, 2024 Cleaner Interference and Foreground Latency in Append-Only Storage How a background collector steals device queue slots from the write path, why the resulting latency spikes are bursty rather than average, and the throttling and scheduling measures that bound them. filesystems
Mar 1, 2024 Nagle's Algorithm and the Delayed Acknowledgement Deadlock Why coalescing small writes and batching acknowledgements interact badly, how the 40 ms delay arises, and which socket options disable each mechanism. networking
Feb 13, 2024 Negotiation Round Trips and What They Cost How capability discovery is paid for in latency, why the cheapest negotiation is one that reuses state, and where a saved round trip becomes a security problem. internet protocols
Feb 17, 2023 Merge Scheduling and Latency-Bounded Throttling How a search engine decides which segments to merge and when, and how it keeps merge I/O from spiking query latency while still reclaiming space fast enough. information retrieval
Jan 30, 2023 Decomposing Path Latency into Propagation, Serialization, and Queueing The four terms that sum to the delay across a network path, how each scales with distance, link rate, and load, and which ones a sender can actually influence. networking
Jan 25, 2023 Communication-Avoiding Algorithms and the Latency Floor How restructuring the arithmetic to block inner products and use fewer global synchronization steps changes the scaling exponent, and what it costs in numerical stability. scientific computing
Dec 21, 2022 Dependent Loads and the Cost of Pointer Chasing Why linked structures serialise the memory system, how a dependent load chain differs from independent accesses, and what prefetchers cannot see. performance engineering
Aug 17, 2022 Counting Round Trips Before the First Payload Byte A cold request on a phone crosses radio setup, name resolution, a transport handshake, and a TLS handshake before any application data moves, and each layer can be shortened. mobile computing