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.
Questions tagged [spinlock]
318 questions
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Inconsistent timings when passing data between two threads
I have a piece of code that I use to test various containers (e.g. deque and a circular buffer) when passing data from a producer (thread 1) to a consumer (thread 2). A data is represented by a struct with a pair of timestamps. First timestamp is…
Cattus
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How to solve the spinlock lockup in SMP,both the irq and function want the lock?
Our system(linux) have a spin_lock lockup/deadlock problem, but I don't have a good idea to solve it.
The spinlock can be get in irq and a data transmit function. The lockup happened when:
The app is going to transmit data, then it acquired the…
TonyHo
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Hybrid mutex library for Linux
Is there any standard threading library for Linux which implements hybrid mutex capabilities? I mean, a mutex which, at first, "behaves like a spinlock" and "only if the lock has still not been obtained after a certain amount of time (or retries or…
LuisABOL
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Debugging simplified version of Lamport's Bakery Algorithm in C
I'm trying to implement a simplified version of Lamport's Bakery Algorithm in C before I attempt to use it to solve a more complex problem.* The simplification I am making is that the lock is only shared by only two threads instead of N.
I set up…
Glenn
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SpinLock in C#. In which type of algorithm SpinLock is a better choice against Monitor?
Possible Duplicate:
Why everyone states that SpinLock is faster?
This question is concerning SpinLock, Monitor & Interlocked.
I made 2 tests which test the performance of Monitor, SpinLock and Interlocked and these tests have left me confused.
My…
Rauf
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Seconds overflow in pthread_cond_timedwait
I have a usecase in which I want to acquire a condition variable and release it after some time interval( Eg: I have a queue of time ordered events and I want to block for a specified duration .)
Duration = Earliest Time in Q - Current Time()
I…
KodeWarrior
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Is it safe to call a non-void function inside kernel without assigning to variable
I am trying to debug a kernel code, because of a "scheduling while in atomic" that is crashing my system. In some point of an actual kernel module I added a line for calling a function defined in another kernel module (this one made by me). The call…
jeanc
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Shared Counter Gives Different Value With Spinlocks
I have the following code:
#include
#include
#define THREAD_CNT 10
#define ITER 100
#define PRINT 1
int lock;
unsigned long long int counter;
void spin_lock(int *p) {
while(!__sync_bool_compare_and_swap(p, 0, 1));
}
void…
aqua
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Disabling the scheduler to reduce the cpu time on spinlock
In linux, in kvm environment, when a process in VM locks on some resource and is pre-empted, other processes of VM, which need that locked resource would spend time on spinlock. And the process would unlock the resource when it's allotted the…
rAzOr
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Multithreading error: Why is there more than one thread in a loop where I expected only one at a time?
Offending code:
object _objLock = new object();
bool _isCurrentlyUpdatingValues = false;
public void UpdateTestReadValuesTimerCallback(object state)
{
try
{
lock (_objLock)
{
if (_isCurrentlyUpdatingValues ==…
Eric Ouellet
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What kind of functions cannot be used in the critical section of the spin lock?
I'm kind of confused about what sort of functions are not allowed in a spin lock's critical section.
In particular I'm confused about reentrant functions. I thought that all reentrant functions are unsafe to use in a spin lock's critical section,…
Shisui
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Do the glibc implementation of pthread_spin_lock() and pthread_spin_unlock() function have memory fence instructions?
Do the glibc implementation of pthread_spin_lock() and pthread_spin_unlock() function have memory fence instructions? (I could not find any fence instructions.)
Similar question has answers here.
Does pthread_mutex_lock contains memory fence…
Hiro Yoshioka
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What exact "resources" are released, when calling pthread_spin_destroy()?
I have a question regarding the phread_spin_destroy() function. In the posix standard it is defined as follows:
The pthread_spin_destroy() function shall destroy the spin lock referenced by lock and release any resources used by the lock.
So if…
lospollos
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which processor will acquire the spinlock?
In a 4 processor system, which of the three processor (all the 3 processors are spinning to acquire the spin lock) will acquire the spinlock released by the fourth processor?
Madara
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Pre-emption can occur if the code exceeds the time slice intended for it, then how do we ensure code length/execution time in the spinlock?
--> Re-editing my question. I thought to picture my understanding. Here is the picture. Please correct me here. By task, I mean process only. A picture is worth a thousand words.
What will happen in the multi-processor, if the third process wants…
dexterous
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