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What's the best way to get the last element of an array without deleting it?
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@DavidMurdoch Perhaps, but it sure does churn the RAM and CPU, creating the temp array for the array values...
– Theodore R. Smith
May 5 '12 at 2:46
13
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Fastest hash for non-cryptographic uses?
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if you have the benefit/luxury of a newer Intel cpu, there is a crc32c assembly command that is...probably really fast (though isn't the traditional crc32 value). See also xxhash code.google.com/p/xxhash
– rogerdpack
Dec 2 '13 at 20:...
Java 8 Streams: multiple filters vs. complex condition
...arge array 1,000,000 elements throughput ops/s:
NOTE: tests runs on
8 CPU
1 GB RAM
OS version: 16.04.1 LTS (Xenial Xerus)
java version: 1.8.0_121
jvm: -XX:+UseG1GC -server -Xmx1024m -Xms1024m
UPDATE:
Java 11 has some progress on the performance, but the dynamics stay the same
Benchmark mo...
How to pass objects to functions in C++?
...fying its value while the function is being executed.
The downside is the CPU cycles and extra memory spent to copy the object.
Pass by const reference:
void func (const vector& v);
This form emulates pass-by-value behavior while removing the copying overhead. The function gets read access ...
What does the git index contain EXACTLY?
...ex Entry Offset Table (IEOT) extension
This patch enables addressing the CPU cost of loading the index by adding
additional data to the index that will allow us to efficiently multi-
thread the loading and conversion of cache entries.
It accomplishes this by adding an (optional) index extension th...
Best practices for circular shift (rotate) operations in C++
...shld edi,edi,7 which is slower and takes more bytes than rol edi,7 on some CPUs (especially AMD, but also some Intel), when BMI2 isn't available for rorx eax,edi,25 to save a MOV.
MSVC: x86-64 CL19: Only recognized for constant-count rotates. (The wikipedia idiom is recognized, but the branch and A...
Why is it bad practice to call System.gc()?
...the garbage collector explicitly. Calling the GC at the wrong time wastes CPU cycles. You (the programmer) do not have enough information to determine when the right time is ... but the JVM does.
– Stephen C
Oct 6 '11 at 8:16
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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...