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Oprofile
In computing, OProfile is a system-wide statistical profiling tool for Linux. John Levon wrote it in 2001 for Linux kernel version 2.4 after his M.Sc. project; it consists of a kernel module, a user-space daemon and several user-space tools. Details OProfile can profile an entire system or its parts, from interrupt routines or drivers, to user-space processes. It has low overhead. The most widely supported kernel mode of uses a system timer (See: Gathering profiling events). However, this mode is unable to measure kernel functions where interrupts are disabled. Newer CPU models support a hardware performance counter mode which uses hardware logic to record events without any active code needed. In Linux 2.2/2.4 only 32-bit x86 and IA64 are supported; in Linux 2.6 there is wider support: x86 (32 and 64 bit), DEC Alpha, MIPS, ARM, sparc64, ppc64, AVR32. Call graphs are supported only on x86 and ARM. In 2012 two IBM engineers recognized OProfile as one of the two most c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perf (Linux)
perf (sometimes called perf_events or perf tools, originally Performance Counters for Linux, PCL) is a performance analyzing tool in Linux, available from Linux kernel version 2.6.31 in 2009. Userspace controlling utility, named perf, is accessed from the command line and provides a number of subcommands; it is capable of statistical profiling of the entire system (both kernel and userland code). It supports hardware performance counters, tracepoints, software performance counters (e.g. hrtimer), and dynamic probes (for example, kprobes or uprobes). In 2012, two IBM engineers recognized perf (along with OProfile) as one of the two most commonly used performance counter profiling tools on Linux. Implementation The interface between the perf utility and the kernel consists of only one syscall and is done via a file descriptor and a mapped memory region.Roberto A. Vitillo ( LBNL)PERFORMANCE TOOLS DEVELOPMENTS 16 June 2011, presentation from "Future computing in particle phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Performance Analysis Tools
This is a list of performance analysis tools for use in software development. General purpose, language independent The following tools work based on log files that can be generated from various systems. * time (Unix) - can be used to determine the run time of a program, separately counting user time vs. system time, and CPU time vs. clock time. *timem (Unix) - can be used to determine the wall-clock time, CPU time, and CPU utilization similar to time (Unix) but supports numerous extensions. ** Supports reporting peak resident set size, major and minor page faults, priority and voluntary context switches via getrusage. ** Supports sampling procfs on supporting systems to report metrics such as page-based resident set size, virtual memory size, read-bytes, and write-bytes, etc. ** Supports collecting hardware counters when built with PAPI support. Multiple languages The following tools work for multiple languages or binaries. C and C++ * Arm MAP, a performance profiler s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Profiling (computer Programming)
In software engineering, profiling ("program profiling", "software profiling") is a form of dynamic program analysis that measures, for example, the space (memory) or time complexity of a program, the usage of particular instructions, or the frequency and duration of function calls. Most commonly, profiling information serves to aid program optimization, and more specifically, performance engineering. Profiling is achieved by instrumenting either the program source code or its binary executable form using a tool called a ''profiler'' (or ''code profiler''). Profilers may use a number of different techniques, such as event-based, statistical, instrumented, and simulation methods. Gathering program events Profilers use a wide variety of techniques to collect data, including hardware interrupts, code instrumentation, instruction set simulation, operating system hooks, and performance counters. Use of profilers The output of a profiler may be: * A statistical '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian, Fedora Linux, and Ubuntu, the latter of which itself consists of many different distributions and modifications, including Lubuntu and Xubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIPS Architecture
MIPS (Microprocessor without Interlocked Pipelined Stages) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA)Price, Charles (September 1995). ''MIPS IV Instruction Set'' (Revision 3.2), MIPS Technologies, Inc. developed by MIPS Computer Systems, now MIPS Technologies, based in the United States. There are multiple versions of MIPS: including MIPS I, II, III, IV, and V; as well as five releases of MIPS32/64 (for 32- and 64-bit implementations, respectively). The early MIPS architectures were 32-bit; 64-bit versions were developed later. As of April 2017, the current version of MIPS is MIPS32/64 Release 6. MIPS32/64 primarily differs from MIPS I–V by defining the privileged kernel mode System Control Coprocessor in addition to the user mode architecture. The MIPS architecture has several optional extensions. MIPS-3D which is a simple set of floating-point SIMD instructions dedicated to common 3D tasks, MDMX (MaDMaX) which is a more ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gprof
Gprof is a performance analysis tool for Unix applications. It used a hybrid of instrumentation and samplingSusan L. Graham, Peter B. Kessler, and Marshall K. Mckusick''gprof: a Call Graph Execution Profiler''// Proceedings of the SIGPLAN '82 Symposium on Compiler Construction, SIGPLAN Notices, Vol. 17, No 6, pp. 120-126; doi: 10.1145/800230.806987 and was created as an extended version of the older "prof" tool. Unlike prof, gprof is capable of limited call graph collecting and printing. History GPROF was originally written by a group led by Susan L. Graham at the University of California, Berkeley for Berkeley Unix (4.2BSD). Another implementation was written as part of the GNU project for GNU Binutils in 1988 by Jay Fenlason. Implementation Instrumentation code is automatically inserted into the program code during compilation (for example, by using the '-pg' option of the gcc compiler), to gather caller-function data. A call to the monitor function 'mcount' is inserted b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assembly Language
In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per machine instruction (1:1), but constants, comments, assembler directives, symbolic labels of, e.g., memory locations, registers, and macros are generally also supported. The first assembly code in which a language is used to represent machine code instructions is found in Kathleen and Andrew Donald Booth's 1947 work, ''Coding for A.R.C.''. Assembly code is converted into executable machine code by a utility program referred to as an '' assembler''. The term "assembler" is generally attributed to Wilkes, Wheeler and Gill in their 1951 book '' The Preparation of Programs for an Electronic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Code
In computing, source code, or simply code, is any collection of code, with or without comment (computer programming), comments, written using a human-readable programming language, usually as plain text. The source code of a Computer program, program is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source code. The source code is often transformed by an assembler (computing), assembler or compiler into Binary number, binary machine code that can be executed by the computer. The machine code is then available for execution (computing), execution at a later time. Most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user (computing), user, programmer or a system administrator, any of whom might wish to study or modify the program. Alternatively, depending on the technology being used, source code m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardware Performance Counter
In computers, hardware performance counters (HPC), or hardware counters are a set of special-purpose registers built into modern microprocessors to store the counts of hardware-related activities within computer systems. Advanced users often rely on those counters to conduct low-level performance analysis or tuning. Implementations The number of available hardware counters in a processor is limited while each CPU model might have a lot of different events that a developer might like to measure. Each counter can be programmed with the index of an event type to be monitored, like a L1 cache miss or a branch misprediction. One of the first processors to implement such counter and an associated instruction RDPMC to access it was the Intel Pentium, but they were not documented until Terje Mathisen wrote an article about reverse engineering them in ''Byte'' July 1994. The following table shows some examples of CPUs and the number of available hardware counters: Versus software tec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Call Graph
A call graph (also known as a call multigraph) is a control-flow graph, which represents calling relationships between subroutines in a computer program. Each node represents a procedure and each edge ''(f, g)'' indicates that procedure ''f'' calls procedure ''g''. Thus, a cycle in the graph indicates recursive procedure calls. Basic concepts Call graphs can be dynamic or static. A dynamic call graph is a record of an execution of the program, for example as output by a profiler. Thus, a dynamic call graph can be exact, but only describes one run of the program. A static call graph is a call graph intended to represent every possible run of the program. The exact static call graph is an undecidable problem, so static call graph algorithms are generally overapproximations. That is, every call relationship that occurs is represented in the graph, and possibly also some call relationships that would never occur in actual runs of the program. Call graphs can be defined to represent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AVR32
AVR32 is a 32-bit RISC microcontroller architecture produced by Atmel. The microcontroller architecture was designed by a handful of people educated at the Norwegian University of Science and Technology, including lead designer Øyvind Strøm and CPU architect Erik Renno in Atmel's Norwegian design center. Most instructions are executed in a single-cycle. The multiply–accumulate unit can perform a 32-bit × 16-bit + 48-bit arithmetic operation in two cycles (result latency), issued once per cycle. It does not resemble the 8-bit AVR microcontroller family, even though they were both designed at Atmel Norway, in Trondheim. Some of the debug-tools are similar. Support for AVR32 has been dropped from Linux as of kernel 4.12; Atmel has switched mostly to M variants of the ARM architecture. Architecture The AVR32 has at least two micro-architectures, the AVR32A and AVR32B. These differ in the instruction set architecture, register configurations and the use of caches for inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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