2008-10-22 19:37:52

by sbs

[permalink] [raw]
Subject: high %CPU values after upgrading to the last stable kernel

after upgrading from 2.6.16 to 2.6.27 kernel top shows a strange
picture of extremely highly %CPU values.

# top -V
top: procps version 3.2.6


# top
top - 04:24:06 up 7 days, 1:12, 1 user, load average: 2.28, 2.03, 2.00
Tasks: 183 total, 2 running, 181 sleeping, 0 stopped, 0 zombie
Cpu(s): 36.2% us, 2.4% sy, 0.0% ni, 56.1% id, 4.7% wa, 0.1% hi, 0.5% si
Mem: 12473092k total, 11169060k used, 1304032k free, 16k buffers
Swap: 2048248k total, 636k used, 2047612k free, 1257988k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
19824 b 20 0 92212 17m 5420 S 4308 0.1 1:39.49 httpd
14396 b 20 0 92716 28m 16m S 3721 0.2 38:47.38 httpd
14024 b 20 0 92376 28m 16m S 2437 0.2 51:49.68 httpd
7415 b 20 0 96876 40m 24m D 2146 0.3 93:59.72 httpd
8182 b 20 0 94500 36m 21m S 1997 0.3 111:41.60 httpd
13461 b 20 0 94240 31m 17m S 1439 0.3 48:43.71 httpd
8466 b 20 0 92036 32m 21m S 1136 0.3 107:37.90 httpd
17620 b 20 0 92660 23m 11m S 1003 0.2 10:55.03 httpd
14025 b 20 0 92000 28m 16m S 720 0.2 51:49.49 httpd
3808 nobody 20 0 3013m 2.9g 592 S 714 24.7 343030:50 memcached
10 root 15 -5 0 0 0 S 714 0.0 11881:28 ksoftirqd/3
18487 b 20 0 91416 20m 9572 S 580 0.2 8:29.20 httpd
13252 b 20 0 93408 30m 17m S 580 0.3 45:19.69 httpd
17525 b 20 0 93208 23m 10m S 566 0.2 18:34.40 httpd
14760 b 20 0 93452 28m 15m S 534 0.2 57:34.65 httpd
3804 nobody 20 0 2995m 2.9g 592 S 441 24.6 378908:26 memcached
12209 b 20 0 92312 28m 16m S 279 0.2 63:28.45 httpd



%CPU is 4308 here and it's not the highest value.
i havent seen that on any previous kernel on the same server.

should i upgrade procps or downgrade kernel then to get proper values back? :)
or is it a feature of the new kernel?

thank you


2008-10-22 21:05:23

by Frederic Weisbecker

[permalink] [raw]
Subject: Re: high %CPU values after upgrading to the last stable kernel

2008/10/22 sbs <[email protected]>:
> after upgrading from 2.6.16 to 2.6.27 kernel top shows a strange
> picture of extremely highly %CPU values.
>
> # top -V
> top: procps version 3.2.6
>
>
> # top
> top - 04:24:06 up 7 days, 1:12, 1 user, load average: 2.28, 2.03, 2.00
> Tasks: 183 total, 2 running, 181 sleeping, 0 stopped, 0 zombie
> Cpu(s): 36.2% us, 2.4% sy, 0.0% ni, 56.1% id, 4.7% wa, 0.1% hi, 0.5% si
> Mem: 12473092k total, 11169060k used, 1304032k free, 16k buffers
> Swap: 2048248k total, 636k used, 2047612k free, 1257988k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 19824 b 20 0 92212 17m 5420 S 4308 0.1 1:39.49 httpd
> 14396 b 20 0 92716 28m 16m S 3721 0.2 38:47.38 httpd
> 14024 b 20 0 92376 28m 16m S 2437 0.2 51:49.68 httpd
> 7415 b 20 0 96876 40m 24m D 2146 0.3 93:59.72 httpd
> 8182 b 20 0 94500 36m 21m S 1997 0.3 111:41.60 httpd
> 13461 b 20 0 94240 31m 17m S 1439 0.3 48:43.71 httpd
> 8466 b 20 0 92036 32m 21m S 1136 0.3 107:37.90 httpd
> 17620 b 20 0 92660 23m 11m S 1003 0.2 10:55.03 httpd
> 14025 b 20 0 92000 28m 16m S 720 0.2 51:49.49 httpd
> 3808 nobody 20 0 3013m 2.9g 592 S 714 24.7 343030:50 memcached
> 10 root 15 -5 0 0 0 S 714 0.0 11881:28 ksoftirqd/3
> 18487 b 20 0 91416 20m 9572 S 580 0.2 8:29.20 httpd
> 13252 b 20 0 93408 30m 17m S 580 0.3 45:19.69 httpd
> 17525 b 20 0 93208 23m 10m S 566 0.2 18:34.40 httpd
> 14760 b 20 0 93452 28m 15m S 534 0.2 57:34.65 httpd
> 3804 nobody 20 0 2995m 2.9g 592 S 441 24.6 378908:26 memcached
> 12209 b 20 0 92312 28m 16m S 279 0.2 63:28.45 httpd
>
>
>
> %CPU is 4308 here and it's not the highest value.
> i havent seen that on any previous kernel on the same server.
>
> should i upgrade procps or downgrade kernel then to get proper values back? :)
> or is it a feature of the new kernel?
>
> thank you
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> Please read the FAQ at http://www.tux.org/lkml/
>

Hi,

It really depends on what your box is doing at the time you capture
the cpu usage.
And it really depends too of your kernel config...

2008-10-22 22:41:13

by Ray Lee

[permalink] [raw]
Subject: Re: high %CPU values after upgrading to the last stable kernel

On Wed, Oct 22, 2008 at 2:04 PM, Frédéric Weisbecker <[email protected]> wrote:> 2008/10/22 sbs <[email protected]>:>> after upgrading from 2.6.16 to 2.6.27 kernel top shows a strange>> picture of extremely highly %CPU values.>>>> # top -V>> top: procps version 3.2.6>>>>>> # top>> top - 04:24:06 up 7 days, 1:12, 1 user, load average: 2.28, 2.03, 2.00>> Tasks: 183 total, 2 running, 181 sleeping, 0 stopped, 0 zombie>> Cpu(s): 36.2% us, 2.4% sy, 0.0% ni, 56.1% id, 4.7% wa, 0.1% hi, 0.5% si>> Mem: 12473092k total, 11169060k used, 1304032k free, 16k buffers>> Swap: 2048248k total, 636k used, 2047612k free, 1257988k cached>>>> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND>> 19824 b 20 0 92212 17m 5420 S 4308 0.1 1:39.49 httpd>> 14396 b 20 0 92716 28m 16m S 3721 0.2 38:47.38 httpd>> 14024 b 20 0 92376 28m 16m S 2437 0.2 51:49.68 httpd>> 7415 b 20 0 96876 40m 24m D 2146 0.3 93:59.72 httpd>> 8182 b 20 0 94500 36m 21m S 1997 0.3 111:41.60 httpd>> 13461 b 20 0 94240 31m 17m S 1439 0.3 48:43.71 httpd>> 8466 b 20 0 92036 32m 21m S 1136 0.3 107:37.90 httpd>> 17620 b 20 0 92660 23m 11m S 1003 0.2 10:55.03 httpd>> 14025 b 20 0 92000 28m 16m S 720 0.2 51:49.49 httpd>> 3808 nobody 20 0 3013m 2.9g 592 S 714 24.7 343030:50 memcached>> 10 root 15 -5 0 0 0 S 714 0.0 11881:28 ksoftirqd/3>> 18487 b 20 0 91416 20m 9572 S 580 0.2 8:29.20 httpd>> 13252 b 20 0 93408 30m 17m S 580 0.3 45:19.69 httpd>> 17525 b 20 0 93208 23m 10m S 566 0.2 18:34.40 httpd>> 14760 b 20 0 93452 28m 15m S 534 0.2 57:34.65 httpd>> 3804 nobody 20 0 2995m 2.9g 592 S 441 24.6 378908:26 memcached>> 12209 b 20 0 92312 28m 16m S 279 0.2 63:28.45 httpd>>>>>>>> %CPU is 4308 here and it's not the highest value.>> i havent seen that on any previous kernel on the same server.>>>> should i upgrade procps or downgrade kernel then to get proper values back? :)>> or is it a feature of the new kernel?>>>> thank you>>>> Hi,>> It really depends on what your box is doing at the time you capture> the cpu usage.> And it really depends too of your kernel config...
It really shouldn't, we're talking about /proc which is supposed to bea stable userspace interface.
Try upgrading your procps, there's a chance it's just so ancient thatit accidentally got broken. However, if that fixes your problem, thenplease report back with a subject line of "/proc API breakage" orsomesuch, to get the proper attention to the issue.????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?

2008-10-23 01:05:58

by Alistair John Strachan

[permalink] [raw]
Subject: Re: high %CPU values after upgrading to the last stable kernel

On Wednesday 22 October 2008 23:40:54 Ray Lee wrote:
> On Wed, Oct 22, 2008 at 2:04 PM, Fr?d?ric Weisbecker <[email protected]>
wrote:
> > 2008/10/22 sbs <[email protected]>:
[snip]
> >> should i upgrade procps or downgrade kernel then to get proper values
> >> back? :) or is it a feature of the new kernel?
> >>
> >> thank you
> >
> > Hi,
> >
> > It really depends on what your box is doing at the time you capture
> > the cpu usage.
> > And it really depends too of your kernel config...
>
> It really shouldn't, we're talking about /proc which is supposed to be
> a stable userspace interface.
>
> Try upgrading your procps, there's a chance it's just so ancient that
> it accidentally got broken. However, if that fixes your problem, then
> please report back with a subject line of "/proc API breakage" or
> somesuch, to get the proper attention to the issue.

This is a known kernel bug that for some reason wasn't fixed before 2.6.27 was
released. See http://bugzilla.kernel.org/show_bug.cgi?id=11209 for details.

It would probably be useful if the OP added himself to the CC list, so Peter
can get some more details about the box.

--
Cheers,
Alistair.

2008-10-23 14:55:34

by sbs

[permalink] [raw]
Subject: Re: high %CPU values after upgrading to the last stable kernel

thank you
will be waiting until it gets fixed

On Thu, Oct 23, 2008 at 4:55 AM, Alistair John Strachan
<[email protected]> wrote:
> On Wednesday 22 October 2008 23:40:54 Ray Lee wrote:
>> On Wed, Oct 22, 2008 at 2:04 PM, Fr?d?ric Weisbecker <[email protected]>
> wrote:
>> > 2008/10/22 sbs <[email protected]>:
> [snip]
>> >> should i upgrade procps or downgrade kernel then to get proper values
>> >> back? :) or is it a feature of the new kernel?
>> >>
>> >> thank you
>> >
>> > Hi,
>> >
>> > It really depends on what your box is doing at the time you capture
>> > the cpu usage.
>> > And it really depends too of your kernel config...
>>
>> It really shouldn't, we're talking about /proc which is supposed to be
>> a stable userspace interface.
>>
>> Try upgrading your procps, there's a chance it's just so ancient that
>> it accidentally got broken. However, if that fixes your problem, then
>> please report back with a subject line of "/proc API breakage" or
>> somesuch, to get the proper attention to the issue.
>
> This is a known kernel bug that for some reason wasn't fixed before 2.6.27 was
> released. See http://bugzilla.kernel.org/show_bug.cgi?id=11209 for details.
>
> It would probably be useful if the OP added himself to the CC list, so Peter
> can get some more details about the box.
>
> --
> Cheers,
> Alistair.
>