On Tue, 2007-10-30 at 16:36 +0800, Zhang, Yanmin wrote: > On Tue, 2007-10-30 at 08:26 +0100, Ingo Molnar wrote: > > * Zhang, Yanmin <[EMAIL PROTECTED]> wrote: > > > > > sub-bisecting captured patch > > > 38ad464d410dadceda1563f36bdb0be7fe4c8938(sched: uniform tunings) > > > caused 20% regression of aim7. > > > > > > The last 10% should be also related to sched parameters, such like > > > sysctl_sched_min_granularity. > > > > ah, interesting. Since you have CONFIG_SCHED_DEBUG enabled, could you > > please try to figure out what the best value for > > /proc/sys/kernel_sched_latency, /proc/sys/kernel_sched_nr_latency and > > /proc/sys/kernel_sched_min_granularity is? > > > > there's a tuning constraint for kernel_sched_nr_latency: > > > > - kernel_sched_nr_latency should always be set to > > kernel_sched_latency/kernel_sched_min_granularity. (it's not a free > > tunable) > > > > i suspect a good approach would be to double the value of > > kernel_sched_latency and kernel_sched_nr_latency in each tuning > > iteration, while keeping kernel_sched_min_granularity unchanged. That > > will excercise the tuning values of the 2.6.23 kernel as well. > I followed your idea to test 2.6.24-rc1. The improvement is slow. > When sched_nr_latency=2560 and sched_latency_ns=640000000, the performance > is still about 15% less than 2.6.23.
I got the aim7 30% regression on my new upgraded stoakley machine. I found this mahcine is slower than the old one. Maybe BIOS has issues, or memeory(Might not be dual-channel?) is slow. So I retested it on the old machine and found on the old stoakley machine, the regression is about 6%, quite similiar to the regression on tigerton machine. By sched_nr_latency=640 and sched_latency_ns=640000000 on the old stoakley machine, the regression becomes about 2%. Other latency has more regression. On my tulsa machine, by sched_nr_latency=640 and sched_latency_ns=640000000, the regression becomes less than 1% (The original regression is about 20%). When I ran a bad script to change the values of sched_nr_latency and sched_latency_ns, I hit OOPS on my tulsa machine. Below is the log. It looks like sched_nr_latency becomes 0. *******************Log************************************ divide error: 0000 [1] SMP CPU 1 Modules linked in: megaraid_mbox megaraid_mm Pid: 7326, comm: sh Not tainted 2.6.24-rc1 #2 RIP: 0010:[<ffffffff8022c2bf>] [<ffffffff8022c2bf>] __sched_period+0x22/0x2e RSP: 0018:ffff810105909e38 EFLAGS: 00010046 RAX: 000000005a000000 RBX: 0000000000000000 RCX: 000000002d000000 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002 RBP: ffff810105909e40 R08: ffff810103bfed50 R09: 00000000ffffffff R10: 0000000000000038 R11: 0000000000000296 R12: ffff810100d6db40 R13: ffff8101058c4148 R14: 0000000000000001 R15: ffff810104c34088 FS: 00002b851bc59f50(0000) GS:ffff810100cb1b40(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00000000006c64d8 CR3: 000000010752c000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 7326, threadinfo ffff810105908000, task ffff810104c34040) Stack: 0000000000000800 ffff810105909e58 ffffffff8022c2db 00000000079d292b ffff810105909e88 ffffffff8022c36e ffff810100d6db40 ffff8101058c4148 ffff8101058c4100 0000000000000001 ffff810105909ec8 ffffffff80232d0a Call Trace: [<ffffffff8022c2db>] __sched_vslice+0x10/0x1d [<ffffffff8022c36e>] place_entity+0x86/0xc3 [<ffffffff80232d0a>] task_new_fair+0x48/0xa5 [<ffffffff8020b63e>] system_call+0x7e/0x83 [<ffffffff80233325>] wake_up_new_task+0x70/0xa4 [<ffffffff80235612>] do_fork+0x137/0x204 [<ffffffff802818bd>] vfs_write+0x121/0x136 [<ffffffff8023f017>] recalc_sigpending+0xe/0x25 [<ffffffff8023f0ef>] sigprocmask+0x9e/0xc0 [<ffffffff8020b957>] ptregscall_common+0x67/0xb0 Code: 48 f7 f3 48 89 c1 5b c9 48 89 c8 c3 55 48 89 e5 53 48 89 fb RIP [<ffffffff8022c2bf>] __sched_period+0x22/0x2e RSP <ffff810105909e38> divide error: 0000 [2] SMP CPU 0 Modules linked in: megaraid_mbox megaraid_mm Pid: 3674, comm: automount Tainted: G D 2.6.24-rc1 #2 RIP: 0010:[<ffffffff8022c2bf>] [<ffffffff8022c2bf>] __sched_period+0x22/0x2e RSP: 0018:ffff81010690de38 EFLAGS: 00010046 RAX: 000000005a000000 RBX: 0000000000000000 RCX: 000000002d000000 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002 RBP: ffff81010690de40 R08: ffff81010690c000 R09: 00000000ffffffff R10: 0000000000000038 R11: ffff810104007040 R12: ffff810001033880 R13: ffff810100f2a828 R14: 0000000000000001 R15: ffff810104007088 FS: 0000000040021950(0063) GS:ffffffff8074e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00002b6cc4245000 CR3: 0000000105972000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process automount (pid: 3674, threadinfo ffff81010690c000, task ffff810104007040) Stack: 0000000000000800 ffff81010690de58 ffffffff8022c2db 000000057aef240d ffff81010690de88 ffffffff8022c36e ffff810001033880 ffff810100f2a828 ffff810100f2a7e0 0000000000000000 ffff81010690dec8 ffffffff80232d0a Call Trace: [<ffffffff8022c2db>] __sched_vslice+0x10/0x1d [<ffffffff8022c36e>] place_entity+0x86/0xc3 [<ffffffff80232d0a>] task_new_fair+0x48/0xa5 [<ffffffff8020b63e>] system_call+0x7e/0x83 [<ffffffff80233325>] wake_up_new_task+0x70/0xa4 [<ffffffff80235612>] do_fork+0x137/0x204 [<ffffffff8020b957>] ptregscall_common+0x67/0xb0 Code: 48 f7 f3 48 89 c1 5b c9 48 89 c8 c3 55 48 89 e5 53 48 89 fb RIP [<ffffffff8022c2bf>] __sched_period+0x22/0x2e RSP <ffff81010690de38> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
