Forgive me to ask a stupid question. Why using the 24 mainline kernel, the time is less than using the rt-patched kernel? -----Original Message----- From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Steven Rostedt Sent: 2008年5月20日 7:44 To: Kasper Sandberg Cc: LKML; RT; Ingo Molnar; Thomas Gleixner Subject: Re: 2.6.25.4-rt2 On Tue, 20 May 2008, Kasper Sandberg wrote: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 --
| Tarkan Erimer | Re: Dual-Licensing Linux Kernel with GPL V2 and GPL V3 |
| Greg Kroah-Hartman | [PATCH 006/196] Chinese: add translation of oops-tracing.txt |
| Eric Sandeen | Re: [RFC] Heads up on sys_fallocate() |
| YOSHIFUJI Hideaki / | request_module: runaway loop modprobe net-pf-1 (is Re: Linux 2.6.21-rc1) |
git: | |
| Gerrit Renker | [PATCH 0/37] dccp: Feature negotiation - last call for comments |
| Jarek Poplawski | Re: [PATCH] pkt_sched: Destroy gen estimators under rtnl_lock(). |
| Ben Greear | Re: MACVLANs really best solution? How about a bridge with multiple bridge virtual... |
| Rafael J. Wysocki | 2.6.29-rc8: Reported regressions from 2.6.28 |
