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Performance optimization strategies of last resort [closed]
...t's hard to sample, so I give it 10 times as much work to do, but the following times are based on the original workload.
More diagnosis reveals that it is spending time in queue-management. In-lining these reduces the time to 7 seconds.
Now a big time-taker is the diagnostic printing I had been d...
Determining complexity for recursive functions (Big O notation)
...4, even though the result is the same, shouldn't the induction be the following? T(n) = a + 2T(n-1) = a + 2a + 4T(n-1) = 3a + 4a + 8T(n-1) = a * (2^n - 1) + 2^n * T(0) = a * (2^n - 1) + b * 2^n = (a + b) * 2^n - a = O(2^n)
– Snowfish
Jan 3 at 22:59
...
Mutex example / tutorial? [closed]
...le concurrently, we have potential for a race condition. Consider the following code
//somewhere long ago, we have i declared as int
void my_concurrently_called_function()
{
i++;
}
The internals of this function look so simple. It's only one statement. However, a typical pseudo-assembly languag...
Should I use tag for icons instead of ? [closed]
...t day to learn twitter's bootstrap and it feels bad that they are not following best practices.
– Jashwant
Jun 21 '12 at 9:35
25
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How do I find where an exception was thrown in C++?
...and often is, located in a different function/method than the point of throwing. It has also been pointed out to me in the comments (thanks Dan) that it is implementation-defined whether or not the stack is unwound before terminate() is called.
Update: I threw together a Linux test program called t...
“Keep Me Logged In” - the best approach
... show how absurdly large that number is, let's imagine every server on the internet (let's say 50,000,000 today) trying to brute-force that number at a rate of 1,000,000,000 per second each. In reality your servers would melt under such load, but let's play this out.
guesses_per_second = servers * ...
Optimise PostgreSQL for fast testing
...s as fsync=off without the giant data corruption risk. You do have a small window of loss of recent data if you enable async commit - but that's it.
If you have the option of slightly altering the DDL, you can also use UNLOGGED tables in Pg 9.1+ to completely avoid WAL logging and gain a real speed...
Why do pthreads’ condition variable functions require a mutex?
...ed before you do a wait.
The wait will "atomically" unlock the mutex, allowing others access to the condition variable (for signalling). Then when the condition variable is signalled or broadcast to, one or more of the threads on the waiting list will be woken up and the mutex will be magically loc...
Detect if Visual C++ Redistributable for Visual Studio 2012 is installed
...e of these reg locations may be OS-dependent. I collected this info from a Windows 10 x64 box. I'm just going to go ahead and dump all of these redist versions and the reg keys I search for to detect installation.:
Visual C++ 2005
Microsoft Visual C++ 2005 Redistributable (x64)
Registry Key: HKL...
Multi-gradient shapes
I'd like to create a shape that's like the following image:
5 Answers
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