Performance optimization, benchmarking, profiling, and code efficiency.
iOS deliberately restricts direct access to CPU clock speeds through its public APIs — Apple treats this as implementation detail rather than user-facing information. That said, there are legitimate approaches depending on your needs. Xcode Instruments for Developers If you’re developing for iOS, connect your iPhone to a Mac with Xcode and use Instruments to…
CPU affinity pins a process to specific CPU cores, reducing context switches and improving cache locality. This matters when you need consistent latency or want to isolate workloads on multi-core systems. Using taskset taskset is the standard tool for setting CPU affinity on running processes. The basic syntax: taskset -p -c 0,1,2 <pid> This binds…
The HDFS NameNode holds the entire filesystem namespace and block map in memory. Estimating memory requirements accurately is critical for cluster planning and preventing out-of-memory failures that can cripple your entire cluster. Core Memory Components The NameNode’s memory consumption breaks down into several key areas: Namespace Objects: The NameNode maintains an in-memory representation of the…
These are often confused terms in concurrent programming and multiprocessor systems, but they address different problems in shared memory architectures. Memory Coherence deals with writes to the same memory location. A cache-coherent system ensures that any read of a data location returns the most recently written value. If CPU A writes to address X, then…
The NAS Parallel Benchmarks (NPB) remain a standard tool for evaluating HPC system performance, though landscape has shifted toward additional metrics like HPCG and memory bandwidth tests. This guide covers installation and basic usage. Prerequisites Before installing NPB, you’ll need: Fortran compiler — gfortran is the standard choice on most systems MPI implementation — OpenMPI…
Emacs startup time matters when you’re opening files frequently from the command line or in scripts. A few targeted optimizations can reduce perceived startup overhead from seconds to near-instant. Run Emacs as a daemon with emacsclient The most effective optimization is the server/client architecture. Start Emacs once as a daemon, then reuse that instance for…
Network speed varies dramatically across connection types. Here’s a practical breakdown of real-world performance across different technologies, using actual test data and modern measurement approaches. Historical Context and Modern Relevance While 2G and 3G networks are largely deprecated in most developed regions by 2026, understanding their performance characteristics remains relevant for: Legacy system maintenance in…