On Mon, Mar 10, 2003 at 01:55:31PM +0100, Ralf Baechle wrote: > On Thu, Mar 06, 2003 at 05:40:01PM -0800, Jun Sun wrote: > > > I reported this bug last May. Apparently it is still not > > taken up-stream. Ralf, why don't we fix it here and push > > it up from you? > > > > BTW, this bug actually has effect on real-time performance under > > preemptible kernel. > > < = 2.4.x preemptible kernel is OPP. > > > It can delay the execution of the highest > > priority real-time process from execution up to 1 jiffy. > > Quite a number of users get_cycles() in the kernel assume it to return a > 64-bit number. I guess we'll have to fake a 64-bit counter in software ... > Whether we fake 64-bit or not, oldest_idle is declared as cycles_t. So comparing it with (cycles_t)-1 should be always be correct. And it actually makes a correct C program. :-) I don't see any possible reason for rejecting the change. My previous report is probably just lost in the noise. Jun
