race-condition

问题 I recently started working with OpenMP to do some 'research' for an project in university. I have a rectangular and evenly spaced grid on which I'm solving a partial differential equation with an iterative scheme. So I basically have two for-loops (one in x- and y-direction of the grid each) wrapped by a while-loop for the iterations. Now I want to investigate different parallelization schemes for this. The first (obvious) approach was to do a spatial a parallelization on the for loops. Works

问题 The following code is supposed to prevent Data Racing by using the synchronized method on common. But for some reason the output is always 19915-19980. Shouldn't it be 20000 if it was not data racing? public class SyncVarDataRace extends Thread { private static int common = 0; public void run(){ synchronized((Integer)common){ int local = common; local+=1; common = local; } } public static void main(String[] args) throws InterruptedException { SyncVarDataRace[] allThreads = new SyncVarDataRace

问题 I would like some help identifying why this particular code, in rare circumstances, produces a race condition. I've found a fix, which I'll outline as well, but I really want to understand it. We have a CMS based system comprised of many modules loosely based off a fusebox model. Everything runs through a single index.cfm. In our Index.cfm we are creating a couple instances of Components, some are bsaed on the APPLICATION.PortalApp instance created in Application.cfc. I'm not including that

问题 I am battling with race condition protection in PHP. My application is written in symfony 1.4 and PHP locks session data until a page completes processing. I have a long running (~10 second) login script and I want to display a progress bar showing the user what is being done while they wait. (I want to actually display what is being done and not use a standard [faux] loading bar.) Whenever a script calls session_start() , PHP locks that user's session data until that script completes. This

问题 I'm trying to write a query that updates a row in the "claim" table to an active status only if a user doesn't have more than two active claims open already. So it's very important for data integrity that a user never has more than two active claims open at any given time. I'm running this query in a concurrent environment, so it's possible that two processes execute this query at the same time. I'm also running it under the default Read Committed isolation level. I'm wondering if I'm open to

问题 I'm analysing the following pseudocode for race conditions (a bit of self practise) and looking at where the possibilities are. The pseudocode describes a vague asynchronous reader/writer. Writer Thread r = 0; w = 1; l = 2; //assign start slot numbers while(1) { write_slot(w); l = w; //last written slot is w w = not(r,l) //assigns next slot so that w is neither r or l } Reader Thread while(1) { r = l; //read from latest write read(r); } The possibilities of corruption/race conditions I've

问题 GOAL : 1) Enable users to play my game regardless of poor connectivity, and 2) have ~reliable user state stored on Parse for customer support and stats. My Approach : I am using local client storage as the master (so that net connectivity is not required), and I am using Parse as a secondary synced storage so that I can address customer issues and maintain stats. The game has a sequence of fixed levels. User state for each level is stored locally in UserDefaults as the SOT (yes, a bit ugly).

问题 I have a problem. I need to implement a program that switches ucontext threads using a timer and SIGALRM but I am getting a segmentation fault when I switch threads using my evict_thread function. I believe it is the result of a race condition as it occurs at different times durings the programs execution. Here is my evict_thread void evict_thread(int signal) { // Check that there is more than one thread in the queue if ((int)list_length(runqueue) > 1) { // Remove the currently executing

问题 i have an issue with a parallel foreach closing the connection before it finishes executing. when i had a regular foreach loop runnung it was slow but it would return everything. once i changed to a parallel foreach it is now returning about 95% of the data and terminating. below is the code that i am using: var USPostalCodes = repository.GetUSPostalCodes(); var CAPostalCodes = repository.GetCAPostalCodes(); Parallel.ForEach(spreadsheetinfo, location => { LocationData Locationdata = new

问题 This is the php implementation of the same scheduler. I made this php implementation, because I thought I have issue with nodejs async nature. Unfortunately, they have the same issue. This may indicate that something wrong with my logic or mysql. I had hard time to figure why. I have 10 commands stored in schedule table. When the day code, hour and minute are matching up with current day code, hour and minute. Those commands will copy into command table. This relies on the scheduler I am