1Tick=多少秒

[Xx哼哼xX]

在测试软件性能上，为了看执行时间，我调用了GetTickCount，可是1Tick应该是多少秒呢？在网上搜了一些资料，都说1Tick=55ms，我觉得不太对吧。是不是不同的系统，这个值应该是不同的吧，我想问问Server2008上，1Tick应该是多少？

[hilevel]

MSDN上是这么说的
The resolution of the system timer is based on the OEMs setting. Check with the OEM for details.

看来是由硬件决定的

[一条晚起的虫]

// The return value is the number of milliseconds that have elapsed since the system was started
// The resolution of the GetTickCount function is limited to the resolution of the system timer, which is typically in the range of 10 milliseconds to 16 milliseconds.

// 1 tick就是1ms，GetTickCount的典型精度是10-16ms

[hilevel]

QueryPerformanceFrequency好像可以得到这个值

QueryPerformanceFrequency
This function retrieves the frequency, in counts per second, of the high-resolution performance counter.

BOOL QueryPerformanceFrequency (
LARGE_INTEGER *lpliFrequency );
Parameters
lpliFrequency
[out] Points to a variable that the function sets to the current frequency of the performance counter; the frequency is given in counts per second. If the installed hardware does not support a high-resolution performance counter, this parameter can be set to zero.
Return Values
TRUE if the installed hardware supports a high-resolution performance counter; otherwise FALSE.

Remarks
The Platform Builder includes a default implementation of this function. In some cases, the QueryPerformanceCounter functionality is implemented by using GetTickCount. In these cases, a call to this function returns 1,000 (1,000 ticks per second).

The default implementation of QueryPerformanceFrequency can be replaced by defining a custom high-resolution timer function based on the target device’s CPU. The custom high-resolution timer functions must be implemented in the OAL code and then be exposed to the kernel. To do this, the kernel exposes the global variable pQueryPerformanceFrequency.

Initialize pQueryPerformanceFrequency to point to the equivalent private function (for example, OEMQueryPerformanceFrequency). This should be initialized in OEMInit. Once pQueryPerformanceFrequency is initialized, it points to the OAL implementation to retrieve the high-resolution timers.

[野男孩]

GetTickCount得到的是系统启动之后到现在的毫秒数

[MYNAMELIULI]

GetTickCount得到的是系统启动之后到现在的毫秒数

[jyh_baoding]

根据不同的系统做差然后自己计算啊

[向立天]

QueryPerformanceFrequency可以得到
就是LARGE_INTEGER的QuadPart
计算毫秒方法是

QueryPerformanceFrequency(&litmp);//获得时钟频率
dff	= (double)litmp.QuadPart;
QueryPerformanceCounter(&litmp);//获得初始值
qt1	= litmp.QuadPart;
//......
QueryPerformanceCounter(&litmp);//获得终止值
qt2	= litmp.QuadPart;
dfm	= (double)(qt2-qt1);
dft	= dfm*1000/dff;//获得对应的时间值

[Sou2012]

GetTickCount的精度是10-16ms

timeGetTime的精度是 1 ms 左右。