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How efficient is locking an unlocked mutex? What is the cost of a mutex?

...bunch of mutexes or a single one for an object. If you have many threads and the access to the object happens often, then multiple locks would increase parallelism. At the cost of maintainability, since more locking means more debugging of the locking. How efficient is it to lock a mutex? I.e....
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How do I find which program is using port 80 in Windows? [duplicate]

... Start menu → Accessories → right click on "Command prompt". In the menu, click "Run as Administrator" (on Windows XP you can just run it as usual), run netstat -anb, and then look through output for your program. BTW, Skype by default tries to use ports 80 and 443 for i...
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How to implement one-to-one, one-to-many and many-to-many relationships while designing tables?

Can anyone explain how to implement one-to-one, one-to-many and many-to-many relationships while designing tables with some examples? ...
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How to parse a CSV file in Bash?

...rds"). One approach to making CSV files more amenable to *nix tools is to convert them to TSV (tab-separated values), e.g. using Excel. – peak Sep 7 '15 at 3:27 ...
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How to read and write INI file with Python3?

I need to read, write and create an INI file with Python3. 6 Answers 6 ...
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What is a “static” function in C?

...minology never uses the word "method"; that's Java terminology -- in C++ standard documents it is always called "member function" (see this answer or this glossary of C++ vs Java terms (e.g. C++ uses "data member" and Java uses "field", etc)). – ShreevatsaR Jan...
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Task not serializable: java.io.NotSerializableException when calling function outside closure only o

...sk to fail. Now this doesn't mean that you can serialise an RDD with Spark and avoid NotSerializableException Spark is a distributed computing engine and its main abstraction is a resilient distributed dataset (RDD), which can be viewed as a distributed collection. Basically, RDD's elements are par...
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Clear file cache to repeat performance testing

...ther completely clear, or selectively remove cached information about file and directory contents. 9 Answers ...
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What does the keyword “transient” mean in Java? [duplicate]

...hrough the network, the object needs to be 'serialized'. Serialization converts the object state to serial bytes. Those bytes are sent over the network and the object is recreated from those bytes. Member variables marked by the java transient keyword are not transferred, they are lo...
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PHP - add item to beginning of associative array [duplicate]

... @Timo Huovinen, array_merge didn't work because PHP converted your key to a number, and array_merge resets numeric keys. – meustrus Jan 24 '14 at 18:16 4 ...