smp preempt

x86_64 x86_64 GNU/LinuxOr,Linux Middlebin-Ubuntu 2.6.38-10-generic #46-Ubuntu SMP Tue Jun 28 15:05:41 UTC 2011 i686 athlon i386 GNU/LinuxOr,Linux host 3.13.7-1-ARCH #1 PREEMPT Mon Mar 8 07:07:07 MDT 2012 armv5tel GNU/LinuxUname is the command of used in Linux to print the name, version and other details about the Operating system running on it. The version of Linux kernel is installed on the system can is

refers to the internal core structure is the same, this structure is currently widely used in PC multi-core processors, while heterogeneous refers to the internal core structure is different, this structure is often used in the embedded domain, common embedded processor +DSP core. In this paper, an embedded multi-core processor is used to implement the same code on different processors in a homogeneous structure. Figure 1 ARM SMP processor architect

Concurrency and competition occur in two types of systems: multiple CPUs with symmetric multiprocessor (SMP) A single CPU system that the kernel can preempt The area of code that accesses a shared resource is called the critical section (critical Sections), and the critical section needs to be protected with some kind of mutex mechanism. in a driver, when multiple threads access the sa

(1) Linux hierarchy:(2) The Linux kernel consists of:It consists of 5 subsystems, such as process scheduling (SCHED), memory Management (MM), virtual file system (VFS), network Interface (NET), and interprocess communication (IPC).(3) Differences with UNIX: Linux supports dynamic loading of kernel modules Supports symmetric multi-processing (SMP) mechanisms The Linux kernel can preempt

message. Once the parent process calls WAIT4 (), the process descriptor is freed.5) task_stopped (stop)--the process stops executing and the process is not operational or operational. Usually this state occurs when a signal such as Sigstop,sigtstp,sigttin,sigttou is received. In addition, any signal received during debugging will cause the process to enter this state.The status of the process needs to be adjusted, preferably using the Set_task_state (task, state) function, which, when necessary

First, prefaceThis paper mainly describes the synchronous processing in the main scheduler (schedule function).Ii. Introduction of process schedulingThere are two kinds of process switching, one is that when a process cannot continue because it needs to wait for a resource, it can only suspend itself (call the schedule function) and raise a task scheduling process. The other is that the process is preempted. The so-called preemption (preempt) is when

Transfer from http://www.ibm.com/developerworks/cn/linux/l-completely-fair-scheduler/index.html?ca=drs-cn-0125A brief history of Linux Scheduler the early Linux Scheduler used the lowest design, and it obviously did not focus on large architectures with many processors, Not to mention Hyper-threading. The 1.2 Linux Scheduler uses circular queues for operational task management, using a cyclic scheduling strategy. This scheduler adds and removes processes that are highly efficient (locks with pr

/expression to format output. I think that these operations is common in any WEB application, so should is included in any simple benchmark test. Below I put links to the source code for all test applications: Go http Web.go Twister web.py Tornado Testing environment The test environment consisted of both PCs (traffic generator and application server) connected using direct Gigabitetherne T link. Generator: 2 x Xeon 2.6 GHz with hyperthreading, Debian SI

kernel state, call functions directly, without message passing. Linux Kernel features - supports dynamic loading of kernel modules - supports symmetric multi-processing (SMP)-The kernel can preempt (preemptive), allowing the kernel to run tasks with the ability to prioritize execution- no distinction between threads and processes5. Linux kernel versionThere

of the tasks, the purpose of the balancing . in the structure that supports SMP, in the function sched_init, call open_softirq, Register SCHED_SOFTIRQ software IRQ with its corresponding callback function Run_rebalance_domains. Scheduler_tick, through function trigger_load_balance at each call function to confirm whether the current jiffies value has been Greater than runqueue the next time you want to touch the next_balance value of the load

during the Prohibition preemption process, the kernel preempt_enable will invoke the preempt_schedule check TIF_NEED_RESCHED flag to trigger the task switching as soon as possible.preempt_disableThere are preempt_enable many kernel contexts, typical and well-known, with various kernel lock implementations, such as Spin lock,mutex,semaphore,r/w Semaphore,rcu. Unlike the User preemption, when the two Kernel preemption situations occur, the running state of the task may have been set to TASK_

) and (3) there is a process into the ready state, then you can choose. When scheduling can only occur in both (1) and (4) cases, the scheduling scenario is called a non-preemption schedule (the presence of a new ready process does not affect the running process), otherwise called a preemption schedule (the new ready process may preempt the current running process's CPU resources). In order to compare different scheduling algorithms, many scheduling

, and heterogeneous refers to the internal core structure is different, this structure is often used in the embedded domain, common embedded processor +DSP core. In this paper, the embedded multi-core processor adopts isomorphic structure to realize parallel execution of the same piece of code on different processors. Figure 1 ARM SMP processor architecture In the current embedded field, the most widely used ARM processor, so the arm dual-core proces

no check. The three statuses correspond to each other. = y, = m, = n in the config file, that is, directly compiled into the kernel image, compiled into LKM, indefinite macros or not compiled. ?? ?? Next I will introduce the configuration items that I think are important to you one by one (most of them are related to desktop performance ). The name of each entry below is represented by its full path in the gconf menu. ?? ?? 1) General setup --> Cpuset support: ?? This entry is y or n, and the C

hubBus 004 Device 002: ID 1c4f: 0002 SiGma Micro Bus 004 Device 003: ID 0e8f: 0016 GreenAsia Inc. 4 port USB 1.1 hub UH-174Bus 004 Device 004: ID 192f: 0416 Avago Technologies, Pte. bus 004 Device 005: ID 0133: 8176 Realtek semiconducorp. rtl8188cu802.11n WLANopenSUSE:/usr/src/linux # uname-aLinux openSUSE. me 2.6.37.1-1.2-desktop #1 smp preempt 10:34:10 + 0100 i686 i686 i386 GNU/Linux First, you must in

} for pid = 2444 comm = "nautilus" scontext = root: system_r: unconfined_t: s0-s0: c0.c255 tcontext = root: system_r: unconfined_t: s0-s0: c0.c255 tclass = process Audit (1167183586.828: 14): avc: granted {execmem} for pid = 2444 comm = "nautilus" scontext = root: system_r: unconfined_t: s0-s0: c0.c255 tcontext = root: system_r: unconfined_t: s0-s0: c0.c255 tclass = process Audit (1167183642.660: 15): avc: granted {execmem} for pid = 2444 comm = "nautilus" scontext = root: system_r: unconfined_t

Reprinted please indicate the source and the author contact: http://blog.csdn.net/mimeppContact information: Yu Tao Keywords: grabserial, console, minicom, embedded Because grabserial is used, record it here for future reference. Grabserial is a python tool that can obtain the time of output information on the console and check the execution time of some functions. : Http://elinux.org/Grabserial Output instance: [8.376117 0.000048] Starting kernel... [0.001022 0.001022] [0.00310

mutex be used only to protect critical section. The semaphore is used to protect a variable, or to synchronize. Public classmutextask{/// ///get a semaphore/// /// name /// time-out (milliseconds) /// Results Public Static BOOLLockup (stringLockname,intTimeoutmill) {Mutex mutex; if(! Mutex.tryopenexisting (Lockname, outmutex)) {Mutex=NewMutex (true, Lockname); } return!mutex. WaitOne (Timeoutmill); } /// ///release Semaphore/// /// name Public S

Author:Liu Hongtao, a gold medal lecturer in the far-sighted embedded School of Huaqing. I. background knowledge of module usage count A module is a kernel function component that can be dynamically loaded and detached during kernel running. 2.6 The Module name in the kernel is *. Ko. When a module is used, it cannot be detached. During programming, you need to use "Count" to describe whether the module is being used. Ii. How to Implement the 2.4 kernel count In the 2.4 kernel, the module uses t

space, so the virtual address of the user space cannot be accessed in the interrupt context. (5) The Interrupt Processing routine should not be set to reentrant (a routine that can be called in parallel or recursively ). When the interrupt occurs, both preempt and irq are disable until the interrupt is returned. The interrupt context and process context are different. Different instances of the interrupt processing routine cannot run concurrently on