Re: [PATCH 3.13 39/40] intel_pstate: Take core C0 time into account for core busy calculation

From: Dirk Brandewie
Date: Wed Feb 19 2014 - 11:41:59 EST


On 02/19/2014 04:52 AM, Stefan Lippers-Hollmann wrote:
Hi

On Tuesday 18 February 2014, Greg Kroah-Hartman wrote:
3.13-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>

commit fcb6a15c2e7e76d493e6f91ea889ab40e1c643a4 upstream.

Take non-idle time into account when calculating core busy time.
This ensures that intel_pstate will notice a decrease in load.

References: https://bugzilla.kernel.org/show_bug.cgi?id=66581
Cc: 3.10+ <stable@xxxxxxxxxxxxxxx> # 3.10+
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

This patch, as part of v3.13.4-rc1 causes a kernel package very early
during the boot on at least sandy-bridge (H67) and ivy-bridge (H77),
the call trace (slightly cut on top, as it doesn't fit on the screen;
copied by hand - so it might contains typos, especially in the
heaxdecimal values) is:


Somehow I fat fingered it and sent an incomplete patch :-(

A replacement is on the way.

--Dirk
RDX: 0000000000000000 RSI: 0000000000006000 RDI: 0000000000002200
RBP: 00000009efce4c2b R08: 0000000a3e90e95c R09: 0000000000017700
R10: 0000000000000026 R11: 000000000000002a R12: 0000000000000000
R13: ffff880408ac4c2b R14: ffff88041f20c388 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88041f200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fff88041f5ff000 CR3: 000000000d510000 CR4: 00000000000407f0
Stack:
00000000fffffffd ffff880408ac4a00 ffff880408ac4800 ffffffff81294b82
ffff880408ac4800 0000000000000000 0000000000000000 0000000000000000
ffffffff812925b3 0000000000000011 ffffffff81578e70 ffff880408ca9de8
Call Trace:
[<ffffffff81294b82>] ? intel_pstate_cpu_init+0x107/0x1c2
[<ffffffff812925b3>] ? __cpufreq_add_dev.isra.23+0x30c/0x676
[<ffffffff81269174>] ? subsys_interface_register+0xab/0xdf
[<ffffffff8106d2df>] ? arch_local_irq_save+0x11/0x17
[<ffffffff81291279>] ? cpufreq_register_driver+0x9e/0x143
[<ffffffff8129438d>] ? core_get_min_pstate+0x19/0x19
[<ffffffff815df06e>] ? intel_pstate_init+0x269/0x397
[<ffffffff815dee05>] ? intel_pstate_setup+0x29/0x29
[<ffffffff810020da>] ? do_one_initcall+0x88/0x123
[<ffffffff81057794>] ? parse_args+0x182/0x236
[<ffffffff815adee1>] ? kernel_init_freeable+0x183/0x208
[<ffffffff815ad721>] ? do_early_param+0x81/0x81
[<ffffffff8136d288>] ? rest_init+0x7c/0x7c
[<ffffffff8136d28d>] ? kernel_init+0x5/0xfa
[<ffffffff8137e1cc>] ? ret_from_fork+0x7c/0x7c
[<ffffffff8136d288>] ? rest_init+0x7c/0x7c
Code: 00 48 6b 41 08 64 48 8b 79 10 49 c1 e1 08 48 f7 f7 31 d2 48 89 c6 48 6b c7 64 49 63 f9 4c 69 ce e8 03 00 00 48 c1 e6 08 48 63 f6 <48> f7 71 18 49 c1 e1 09 4d 63 c9 49 0f af f9 48 8d 50 01 48 c1
RIP [<ffffffff812947c4>] intel_pstate_sample+0xb6/0x104
RSP <ffff880408ca9d28>
---[ end trace 682f24c8e98de9df ]---
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Reverting just this patch from 3.13.4-rc1 fixes the regression.

Regards
Stefan Lippers-Hollmann


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