Thread View: cn.bbs.comp.unix.programming.kernel
1 messages
1 total messages
Started by falls
Thu, 14 Mar 2002 05:43
Re: ��̣����ں˿ռ���λ�õ�ǰϵͳʱ�䣿
Author: falls
Date: Thu, 14 Mar 2002 05:43
Date: Thu, 14 Mar 2002 05:43
47 lines
2471 bytes
2471 bytes
�� �� suzhe (������) �Ĵ������ᵽ: ��
: �����ܰ�, �ϴ�!
: 1 ns ��Ӧ�Ŀ��� 1 G ��Ƶ��ѽ! �ĸ� CPU �ܱ߸ɻ��ˢ������� ns ���ļ�ʱ��ѽ?
: ������Ӳ����ʱ��, ������õ� Matrox ͼ��ɼ����Ͼ���Ӳ����ʱ��. ��Ҳ��
: 100 ns ���ľ���.
������˵�IJ������
�ҵ���˼�ǣ��ҿ�30����̣�ѭ��suspend<->resume��30*1000*2�Σ�һ������ʱ��t1
�ɴ��ҵó������л�ʱ��Ϊ: t2=t1/60000
���ҵ�����RTAI LINUX������466�����ʱ��t2��900ns ����
���ֲ��㷽������
#define LOOPS 1000
#define NR_TASKS 30
static RT_TASK thread[NR_TASKS];
ÿ��task����ں���Ϊ��
static void rt_task(int i) {
while (1)
rt_task_suspend(thread+t);
}
����ʱ��ĺ������£�
//CPU_FREQΪCPU����Ƶ�����ҵ�C466�����ֵ���Ϊ: 466,000,000
hard_cli();
t = rdtsc();
for (i = 0; i < LOOPS; i++) {
for (k = 0; k < NR_TASKS; k++) {
rt_task_resume(thread + k);
}
}
t = rdtsc() - t;
hard_sti();
printk("\n\nFOR %d TASKS: ", NR_TASKS);
printk("TIME %d (ms), SUSP/RES SWITCHES %d, ", \
(int)llimd(t, 1000, CPU_FREQ), 2*NR_TASKS*LOOPS);
printk("SWITCH TIME (INCLUDING FULL FP SUPPORT) %d (ns)\n", \
(int)llimd(llimd(t, 1000000000, CPU_FREQ),1,2*30*LOOPS));
--
[m[37m�� ��Դ:��BBS ˮľ�廪վ smth.org��[FROM: 61.190.81.4][m
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