On Tue, 2 Oct 2007, Ingo Molnar wrote:But sched_yield() on Linux never did what the majority of programmers assumed it would do (give up the CPU to some runnable processes for the rest of the time-slice). Instead, it just appeared to spin in the kernel. Therefore, those who needed a sched_yield(), just used usleep(). Whether or not there is a POSIX definition of sched_yield(), there is a need for something that will give up the CPU and not busy-wait. There are many control applications where state-machines are kept in user-mode code. The code waits for an event. It shouldn't be spinning, wasting CPU time, when the kernel can be doing file and network I/O with the wasted CPU cycles. So, just because sched_yield() doesn't work as expected, is not the reason to get rid of it. Cheers, Dick Johnson Penguin : Linux version 2.6.16.24 on an i686 machine (5592.59 BogoMips). My book : http://www.AbominableFirebug.com/ _ **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. -
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