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Are Exceptions in C++ really slow
... handler)
So, mostly cache misses, and thus not trivial compared to pure CPU code.
Note: for more details, read the TR18015 report, chapter 5.4 Exception Handling (pdf)
So, yes, exceptions are slow on the exceptional path, but they are otherwise quicker than explicit checks (if strategy) in gene...
Caveats of select/poll vs. epoll reactors in Twisted
...are active at any given time.
All this means that epoll will lead to less CPU usage for most workloads. As far as memory usage goes, it's a bit of a toss up. select does manage to represent all the necessary information in a highly compact way (one bit per file descriptor). And the FD_SETSIZE (t...
How do you convert a byte array to a hexadecimal string, and vice versa?
...tation. Its safe variant is about 30% faster than the current leader on my CPU. The unsafe variants are even faster. stackoverflow.com/a/24343727/445517
– CodesInChaos
Jun 21 '14 at 17:12
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how to listen to N channels? (dynamic select statement)
.... While waiting for an input channel to have a value this consumes all the CPU available. The whole point of select on multiple channels (without a default clause) is that it efficiently waits until at least one is ready without spinning.
– Dave C
Jun 29 '18 at...
Quickly find whether a value is present in a C array?
... this doesn't take into account memory delays.
Theory of operation: ARM's CPU design executes most instructions in one clock cycle, but the instructions are executed in a pipeline. C compilers will try to eliminate the pipeline delays by interleaving other instructions in between. When presented wi...
How to create GUID / UUID?
...: 292ms 2961ms
- Note: 500k iterations, results will vary by browser/cpu.
So by my 6th iteration of optimizations, I beat the most popular answer by over 12X, the accepted answer by over 9X, and the fast-non-compliant answer by 2-3X. And I'm still rfc4122 compliant.
Interested in how? I'v...
What are copy elision and return value optimization?
...truction and one matching destruction of the copy are omitted, thus saving CPU time, and one object is not created, thus saving space on the stack frame.
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Please explain the exec() function and its family
...ated with a file block or an entire file.
Process resource utilisation and CPU time consumed is set to zero for the child.
The child also doesn’t inherit timers from the parent.
But what about the child memory? Is a new address space created for a child?
The answers in no. After the fork(), bot...
What is the performance of Objects/Arrays in JavaScript? (specifically for Google V8)
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While running under node.js 0.10 (built on v8) I was seeing CPU usage that seemed excessive for the workload. I traced one performance problem to a function that was checking for the existence of a string in an array. So I ran some tests.
loaded 90,822 hosts
loading config took 0.08...
Algorithm for creating a school timetable
...e same time produced about the same quality.
The calculation (on some 1GHz CPU) would take some 1h to stabilize near 10^+300, generating schedules that looked quite nice, for said 10x10x10 test case.
The problem is easily paralellizable by providing networking facility that would exchange best speci...