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Questions tagged [spinlock]

A spinlock is a lock which causes a thread trying to acquire it to simply wait in a loop ("spin") while repeatedly checking if the lock is available.

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Use of STREXEQ instead of STREX for spinlock implementation in ARM

The following is a sample spin-lock implementation in the ARM manual. Please check here: http://infocenter.arm.com/help/topic/com.arm.doc.genc007826/Barrier_Litmus_Tests_and_Cookbook_A08.pdf . Section on "Use of Wait For Event (WFE) and Send Event…
piscianemperor
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Which spinlock method is more efficient: retry test_and_set(), or spin read-only on test()?

Which spinlock method is better (in terms of efficiency)? #include #define METHOD 1 int main( ) { std::atomic_flag lock { }; #if METHOD == 1 while ( lock.test_and_set( std::memory_order_acquire ) ) { while (…
digito_evo
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'OSSpinLock' was deprecated in iOS 10.0: Use os_unfair_lock() from instead

I went through this Question but the provided solution didn't work. Can someone please explain any alternative approach or proper implementation using os_unfair_lock()? when I am using 'OS_UNFAIR_LOCK_INIT', it seems unavailable. Thanks!
Renuka Pandey
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Why the perf always show _raw_spin_unlock_irqrestore or some other spin unlock function

Does anyone know Why the perf always show _raw_spin_unlock_irqrestore or some other spin unlock function? The spin_unlock implementation is usually simpler compared with spin_lock. If there is high contending on the spin_lock, does not the perf…
JC.wang
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Are the memory barriers correct for this lock?

Is this correct? And am I correct in assuming that applying the memory ordering on the std::atomic_flag does NOT provide synchronization for general-purpose locks? #include class Spinlock { public: Spinlock(): f(ATOMIC_FLAG_INIT) {} …
chbaker0
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Fair Reader-Writer Ticket Spinlock in C++ running slow

I have recently implemented a fair reader-writer ticket-spinlock in C++. The code is fairly simple and I thought it was working great. I have integrated the spinlock into a larger application and I noticed that on some rare occasions, the code is…
Guillaume Holley
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GLSL per-pixel spinlock using imageAtomicCompSwap

OpenGL red book version 9 (OpenGL 4.5) example 11.13 is Simple Per-Pixel Mutex. It uses imageAtomicCompSwap in a do {} while() loop to take a per-pixel lock to prevent simultaneous access to a shared resouce between pixel shader invocations…
Zhibo Shen
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Kernel block device - Falling in deadlock using spinlock

I just implemented a virtual block device and I would like to play with it in order to explore how linux kernel handles block devices. My device is just a memory zone divided in two 512 bytes sectors. I'm using a global structure to store device…
Arkaik
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Windows Filtering Platform Network Slowdown Due to Spinlock

I am writing a Windows Filtering Platform Kernel Mode Driver, the goal of the driver is to capture all traffic on a particular layer, and communicate this traffic back down to user-mode so that it can be further analyses. The driver never needs to…
Dan
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Using Swoole locks in PHP

I'm working on a new project which should be implemented by Swoole extension. Here is the docs for swoole locks: https://www.swoole.co.uk/docs/modules/swoole-lock Here is supported lock types: SWOOLE_FILELOCK: file lock SWOOLE_RWLOCK: read write…
Davis.S
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Disabling all interrupts to protect CPU register state on multi processor systems

I need to ensure in a code portion (in kernel mode) that no one else can modify/check the CR0 register. On a one-processor system I think disabling interrupts is the best. But on multi-processor systems : Is there a way to disable ALL interrupts…
jérôme
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Why CLH Lock need prev-Node in java

This is a typical CLH-Lock in java: public class CLHLock{ private final AtomicReference tail; // why we need this node? private final ThreadLocal myPred; private final ThreadLocal myNode; public CLHLock() { …
user5134456
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Locks around memory manipulation via inline assembly

I am new to the low level stuff so I am completely oblivious of what kind of problems you might face down there and I am not even sure if I understand the term "atomic" right. Right now I am trying to make simple atomic locks around memory…
user1235831
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spin_lock on non-preemtive linux kernels

I read that on a system with 1 CPU and non preemtive linux kernel (2.6.x) a spin_lock call is equivalent to an empty call, and thus implemented that way. I can't understand that: shouldn't it be equivalent to a sleep on a mutex? Even on…
Emiliano
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What does raw_spinlock mean?

I was studying the raw_spinlock struct, which is in /usr/src/linux/include/linux/spinlock_types.h: typedef struct raw_spinlock { arch_spinlock_t raw_lock; #ifdef CONFIG_GENERIC_LOCKBREAK unsigned int break_lock; #endif #ifdef…
JuHyung Son
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