* Hack bench regression with CONFIG_SLUB_CPU_PARTIAL disabled (info only)
@ 2013-07-25 8:00 Raghavendra K T
2013-07-25 11:05 ` Eric Dumazet
0 siblings, 1 reply; 3+ messages in thread
From: Raghavendra K T @ 2013-07-25 8:00 UTC (permalink / raw)
To: netdev, linux-kernel
Cc: David S. Miller, Eric W. Biederman, Eric Dumazet, Al Viro, Gao feng
Hi,
While testing hackbench with 3.11-rc1 I observed hackbench testcase
took too long to complete (32 vcpu kvm guest on 32 core HT off machine).
hackbench 1x degraded by 3 time (40sec vs 112sec)
hackbench 2x degraded by around 20time (90sec vs 1800 sec)
When I bisected, I found that I had CONFIG_SLUB_CPU_PARTIAL
accidentally disabled.
I understand that CONFIG_SLUB_CPU_PARTIAL=y by default and the config
option is to provide determinism for RT kernels and thus it is not a
problem.
But thought of sharing this here so that if somebody runs into same
issue accidently, it would save their time.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Hack bench regression with CONFIG_SLUB_CPU_PARTIAL disabled (info only)
2013-07-25 8:00 Hack bench regression with CONFIG_SLUB_CPU_PARTIAL disabled (info only) Raghavendra K T
@ 2013-07-25 11:05 ` Eric Dumazet
2013-07-25 13:20 ` Raghavendra K T
0 siblings, 1 reply; 3+ messages in thread
From: Eric Dumazet @ 2013-07-25 11:05 UTC (permalink / raw)
To: Raghavendra K T
Cc: netdev, linux-kernel, David S. Miller, Eric W. Biederman,
Eric Dumazet, Al Viro, Gao feng
On Thu, 2013-07-25 at 13:30 +0530, Raghavendra K T wrote:
> Hi,
>
> While testing hackbench with 3.11-rc1 I observed hackbench testcase
> took too long to complete (32 vcpu kvm guest on 32 core HT off machine).
>
> hackbench 1x degraded by 3 time (40sec vs 112sec)
> hackbench 2x degraded by around 20time (90sec vs 1800 sec)
>
> When I bisected, I found that I had CONFIG_SLUB_CPU_PARTIAL
> accidentally disabled.
> I understand that CONFIG_SLUB_CPU_PARTIAL=y by default and the config
> option is to provide determinism for RT kernels and thus it is not a
> problem.
> But thought of sharing this here so that if somebody runs into same
> issue accidently, it would save their time.
Incidentally, what difference do you currently get with SLUB and SLAB ?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Hack bench regression with CONFIG_SLUB_CPU_PARTIAL disabled (info only)
2013-07-25 11:05 ` Eric Dumazet
@ 2013-07-25 13:20 ` Raghavendra K T
0 siblings, 0 replies; 3+ messages in thread
From: Raghavendra K T @ 2013-07-25 13:20 UTC (permalink / raw)
To: Eric Dumazet
Cc: netdev, linux-kernel, David S. Miller, Eric W. Biederman,
Eric Dumazet, Al Viro, Gao feng
On 07/25/2013 04:35 PM, Eric Dumazet wrote:
> On Thu, 2013-07-25 at 13:30 +0530, Raghavendra K T wrote:
>> Hi,
>>
>> While testing hackbench with 3.11-rc1 I observed hackbench testcase
>> took too long to complete (32 vcpu kvm guest on 32 core HT off machine).
>>
>> hackbench 1x degraded by 3 time (40sec vs 112sec)
>> hackbench 2x degraded by around 20time (90sec vs 1800 sec)
>>
>> When I bisected, I found that I had CONFIG_SLUB_CPU_PARTIAL
>> accidentally disabled.
>> I understand that CONFIG_SLUB_CPU_PARTIAL=y by default and the config
>> option is to provide determinism for RT kernels and thus it is not a
>> problem.
>> But thought of sharing this here so that if somebody runs into same
>> issue accidently, it would save their time.
>
> Incidentally, what difference do you currently get with SLUB and SLAB ?
>
tested now,
hackbench 1x is almost 2 times slower (40 vs 93)
hackbench 2x is almost 6times slower (90sec vs 528)
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-07-25 13:13 UTC | newest]
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2013-07-25 8:00 Hack bench regression with CONFIG_SLUB_CPU_PARTIAL disabled (info only) Raghavendra K T
2013-07-25 11:05 ` Eric Dumazet
2013-07-25 13:20 ` Raghavendra K T
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