On Tue, 20 May 2008, Kasper Sandberg wrote: > On Mon, 2008-05-19 at 18:43 -0400, Steven Rostedt wrote: > > We are pleased to announce the 2.6.25.4-rt2 tree, which can be > Forgive me if i ask an obvious stupid question. But what is the status > of this -rt tree for .25 in relation with the BKL stuff? Well, the BKL is still a semaphore in 25. For my hackbench runs, I have: [root@bxrhel51 c]# cat hack-test-2.6.25.4-rt2 Time: 4.937 Time: 4.842 Time: 4.877 Time: 4.905 Time: 4.924 Time: 4.781 Time: 4.927 Time: 4.871 Time: 5.181 Time: 4.866 Which is a bit slower than 2.6.24.7-rt7: [root@bxrhel51 c]# cat hack-test-2.6.24.7-rt7 Time: 4.789 Time: 4.824 Time: 4.807 Time: 4.867 Time: 4.802 Time: 4.799 Time: 4.823 Time: 4.855 Time: 4.873 Time: 4.833 But then I checked the base kernels themselves: [root@bxrhel51 c]# cat hack-test-2.6.24.7 Time: 3.817 Time: 3.921 Time: 3.887 Time: 3.920 Time: 3.874 Time: 3.858 Time: 3.912 Time: 3.926 Time: 3.888 Time: 3.901 [root@bxrhel51 c]# cat hack-test-2.6.25.4 Time: 6.225 Time: 6.319 Time: 6.257 Time: 6.534 Time: 6.077 Time: 6.787 Time: 6.927 Time: 6.218 Time: 5.929 Time: 6.554 Where there's a regression somewhere. For 25, the RT patch is actually *better* than mainline! So I was thinking it had to do with the BKL regression, and then I ran: [root@bxrhel51 c]# cat hack-test-2.6.26-rc3 Time: 6.789 Time: 7.123 Time: 6.197 Time: 5.496 Time: 6.708 Time: 5.609 Time: 6.679 Time: 6.206 Time: 6.351 Time: 5.969 Here it is no better, and the BKL has been converted into a spin lock. But I'm very much busy working on -rt right now to dig deeper into this regression. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
