原始文献 / 论坛帖 / Re: bitcoin auto-renice-ing
Re: bitcoin auto-renice-ing
Bitcointalk · 2010-03-15 18:44:12 UTC
它给每个线程设了不同的优先级。生成线程跑在 PRIO_MIN，其他线程几乎不占 CPU，跑在普通优先级。
#define THREAD_PRIORITY_LOWEST PRIO_MIN
#define THREAD_PRIORITY_BELOW_NORMAL 2
#define THREAD_PRIORITY_NORMAL 0
从 Windows 优先级换算过来的值大概来自这样一张表：
"下表展示了 nice 值与 Win32 优先级的映射。关于 Win32 优先级问题的更多信息，请参阅 SetThreadPriority() 的 Win32 文档。
nice 值 Win32 优先级
-20 到 -16 THREAD_PRIORITY_HIGHEST
-15 到 -6 THREAD_PRIORITY_ABOVE_NORMAL
-5 到 +4 THREAD_PRIORITY_NORMAL
+5 到 +14 THREAD_PRIORITY_BELOW_NORMAL
+15 到 +19 THREAD_PRIORITY_LOWEST"
如果你有更好的值，欢迎建议。
另外，网上有建议说 Linux 上用 PRIO_PROCESS 是因为线程就是进程。如果这话不对，那可能就是它把整个应用的优先级都意外改了的原因。
// threads are processes on linux, so PRIO_PROCESS affects just the one thread
setpriority(PRIO_PROCESS, getpid(), nPriority);
英文原文
It sets different priorities for each thread. The generate threads run at PRIO_MIN. The other threads rarely take any CPU and run at normal.
#define THREAD_PRIORITY_LOWEST PRIO_MIN
#define THREAD_PRIORITY_BELOW_NORMAL 2
#define THREAD_PRIORITY_NORMAL 0
The priorities converted from Windows priorities were probably from a table like this:
"The following table shows the mapping between nice values and Win32 priorities. Refer to the Win32 documentation for SetThreadPriority() for more information on Win32 priority issues.
nice value Win32 Priority
-20 to -16 THREAD_PRIORITY_HIGHEST
-15 to -6 THREAD_PRIORITY_ABOVE_NORMAL
-5 to +4 THREAD_PRIORITY_NORMAL
+5 to +14 THREAD_PRIORITY_BELOW_NORMAL
+15 to +19 THREAD_PRIORITY_LOWEST"
If you have better values, suggestions welcome.
Also, there was some advice on the web that PRIO_PROCESS is used on Linux because threads are processes. If that's not true, maybe it accounts for unexpectedly setting the priority of the whole app.
// threads are processes on linux, so PRIO_PROCESS affects just the one thread
setpriority(PRIO_PROCESS, getpid(), nPriority);