System Performance Tuning Quotes

“Memory is consumed by four things: the kernel, filesystem caches, processes, and intimately shared memory.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“Paging is not necessarily indicative of a problem; it is the action of the page scanner to try and increase the size of the free list by moving inactive pages to disk.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“while a system that is swapping is writing entire processes from memory to disk.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“system that is paging is writing selected, infrequently used pages of memory to disk,”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“kswapd’s behavior is controlled by three parameters, called tries_base, tries_min, and swap_cluster,”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“If a process tries to write to a shared page, it incurs a copy-on-write fault.[5”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“second, the memory cycle time, describes how frequently you can repeat a memory reference.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“The first represents the amount of time required to read or write a given location in memory, and is called the memory access time.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“Buses implement either circuit-switched or packet-switched protocols.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“Threads generally fall into five categories for scheduling: timesharing (ts), interactive (ia), kernel, real-time (rt), and interrupt.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“Every LWP has a kernel thread, but every kernel thread need not have an LWP:”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“Linux addresses this issue by adopting an empirical rule related to the processor’s cache size: the larger the processor’s cache, the longer a process will wait for a piece of time on that processor.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“Caches are organized into equal-sized chunks called lines.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“processor performance doubles roughly every eighteen months, but memory performance doubles roughly every seven years.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“NCA uses a kernel module to transparently cache static web content in a kernel memory buffer, and replies to HTTP document requests for documents in its cache without ever waking up the application web server.”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators

“John Hennessy and David Patterson: they are titled Computer Organization and Design: The Hardware/Software Interface and Computer Architecture: A Quantitative Approach (both published by Morgan Kaufmann).”
― Gian-Paolo D. Musumeci, System Performance Tuning: Help for Unix Administrators