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实现一个简单的服务端推方案 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...时性较差。虽然可以通过加快轮询频率的方式来缓解这个问题，但相应付出的代价也不小：一来会使负载居高不下，二来也会让带宽捉襟见肘。
再来说说Long Polling，如果使用传统的LAMP技术去实现的话，大致如下所示：
Long Pol...
Execution time of C program
...OCKS_PER_SEC is a constant which is declared in <time.h>. To get the CPU time used by a task within a C application, use:
clock_t begin = clock();
/* here, do your time-consuming job */
clock_t end = clock();
double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
Note that this retur...
node.js child process - difference between spawn & fork
...o node processes per core, perhaps more for machines with a good ram clock/cpu clock ratio, or for node processes heavy on I/O and light on CPU work, to minimize the down time the event loop is waiting for new events. However, the latter suggestion is a micro-optimization, and would need careful be...
How many system resources will be held for keeping 1,000,000 websocket open? [closed]
...active socket connections is possible for a properly sized system (lots of CPU, RAM and fast networking) and with a tuned server system and optimized server software.
The number of connections is not the primary problem (that's mostly just a question of kernel tuning and enough memory), it is the p...
VideoRecorder 拓展：前台预览录制 + 后台无预览录制，支持分辨率、码率设...
...率对照表（BitRate）
Quality 预设值
注意事项
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VideoRecorder视频录制拓展
拓展开发起由：有用户询问 千问Max版 说我们有...
微博为什么限制140字(附短信70字限制考) - 创意 - 清泛网 - 专注C/C++及内核技术
微博为什么限制140字(附短信70字限制考)问题的提出申请过那么多的微博，数申请网易微博的动机最不纯，因为它的字数限制不是传说中的140字，而是163个字。当年觉得很可爱，于是就注...问题的提出
申请过那么多的微博，数申...
Debug Error \"pure virtual function call\" 原因解析 - 更多技术 - 清泛...
...函数中抛出异常，不然，我们不得不面对以下两个严重的问题：
二次异常导致程序退出;
遗留下来的未完全销毁的对象与未完成的工作导致的后续问题
pure virtual function call就是这种情况。
但是理想与现实总是有差距的，...
How to return only the Date from a SQL Server DateTime datatype
... access strategies and do not always reveal implicit costs involved in the CPU time taken to perform all the pieces. If both queries are run against a table with millions of rows, the CPU time using DateDiff can be close to 1/3rd of the Convert CPU time!
To see execution plans for queries:
set sho...
Combine two columns of text in pandas dataframe
...[252]: (200000, 2)
UPDATE: new timings using Pandas 0.19.0
Timing without CPU/GPU optimization (sorted from fastest to slowest):
In [107]: %timeit df['Year'].astype(str) + df['quarter']
10 loops, best of 3: 131 ms per loop
In [106]: %timeit df['Year'].map(str) + df['quarter']
10 loops, best of 3: ...
What's the difference between a word and byte?
... or even 12 bit machines.
The byte is the smallest addressable unit for a CPU. If you want to set/clear single bits, you first need to fetch the corresponding byte from memory, mess with the bits and then write the byte back to memory.
The word by contrast is biggest chunk of bits with which a pro...