Hi,
> Look at how slow the raid benchmarks are in dmesg with 8GB of memory!
>
> [ 59.592560] raid6: using algorithm sse2x4 (476 MB/s)
> [ 59.597558] raid5: using function: generic_sse (56.000 MB/sec)
>
> Yikes!
>
> With mem=4096M:
> [ 60.336352] raid6: using algorithm sse2x4 (6804 MB/s)
> [ 60.341345] raid5: using function: generic_sse (8552.000 MB/sec)
>
> What is going on here?
>
> Justin.
I saw a similar effect on a P5 board that could
only cache 64MB of memory a long time ago.
Putting more memory into it made the machine slower
and e.g. made the sym2 driver giving up at initialization.
Maybe it's a modern reincarnation of the problem?
Best regards,
Zolt?n B?sz?rm?nyi
On Wed, 30 May 2007, Zoltan Boszormenyi wrote:
> Hi,
>
>> Look at how slow the raid benchmarks are in dmesg with 8GB of memory!
>>
>> [ 59.592560] raid6: using algorithm sse2x4 (476 MB/s)
>> [ 59.597558] raid5: using function: generic_sse (56.000 MB/sec)
>>
>> Yikes!
>>
>> With mem=4096M:
>> [ 60.336352] raid6: using algorithm sse2x4 (6804 MB/s)
>> [ 60.341345] raid5: using function: generic_sse (8552.000 MB/sec)
>>
>> What is going on here?
>>
>> Justin.
>
> I saw a similar effect on a P5 board that could
> only cache 64MB of memory a long time ago.
> Putting more memory into it made the machine slower
> and e.g. made the sym2 driver giving up at initialization.
> Maybe it's a modern reincarnation of the problem?
>
> Best regards,
> Zolt?n B?sz?rm?nyi
>
I see, so Intel 965 motherboards do not work with 8GB of memory? Or is
this a Linux issue?
I have an Intel Case ID open 225446 but so far we have not gotten anywhere
with this problem. Currently I have 8GB in the machine and boot with
mem=4096M. Was there any type of fix? Any recommendations as to what I
can do? Continue to speak with Intel? Or perhaps someone with more
knowledge of the kernel and chime in as to what exactly is happening here?
Justin.
Justin Piszcz ?rta:
>
>
> On Wed, 30 May 2007, Zoltan Boszormenyi wrote:
>
>> Hi,
>>
>>> Look at how slow the raid benchmarks are in dmesg with 8GB of memory!
>>>
>>> [ 59.592560] raid6: using algorithm sse2x4 (476 MB/s)
>>> [ 59.597558] raid5: using function: generic_sse (56.000 MB/sec)
>>>
>>> Yikes!
>>>
>>> With mem=4096M:
>>> [ 60.336352] raid6: using algorithm sse2x4 (6804 MB/s)
>>> [ 60.341345] raid5: using function: generic_sse (8552.000 MB/sec)
>>>
>>> What is going on here?
>>>
>>> Justin.
>>
>> I saw a similar effect on a P5 board that could
>> only cache 64MB of memory a long time ago.
>> Putting more memory into it made the machine slower
>> and e.g. made the sym2 driver giving up at initialization.
>> Maybe it's a modern reincarnation of the problem?
>>
>> Best regards,
>> Zolt?n B?sz?rm?nyi
>>
>
> I see, so Intel 965 motherboards do not work with 8GB of memory? Or
> is this a Linux issue?
It was certainly a mainboard problem, the same system worked well
on another board with a more capable L2 cache controller.
Or on PPro/P-II boards.
> I have an Intel Case ID open 225446 but so far we have not gotten
> anywhere with this problem. Currently I have 8GB in the machine and
> boot with mem=4096M. Was there any type of fix? Any recommendations
> as to what I can do? Continue to speak with Intel? Or perhaps
> someone with more knowledge of the kernel and chime in as to what
> exactly is happening here?
>
> Justin.
I think continue to talk Intel and with the kernel guys,
I don't have experience with machines with so much memory (yet).
Best regards,
Zolt?n B?sz?rm?nyi
On Wed, 30 May 2007, Justin Piszcz wrote:
>
>
> On Wed, 30 May 2007, Zoltan Boszormenyi wrote:
>
>> Hi,
>>
>>> Look at how slow the raid benchmarks are in dmesg with 8GB of memory!
>>>
>>> [ 59.592560] raid6: using algorithm sse2x4 (476 MB/s)
>>> [ 59.597558] raid5: using function: generic_sse (56.000 MB/sec)
>>>
>>> Yikes!
>>>
>>> With mem=4096M:
>>> [ 60.336352] raid6: using algorithm sse2x4 (6804 MB/s)
>>> [ 60.341345] raid5: using function: generic_sse (8552.000 MB/sec)
>>>
>>> What is going on here?
>>>
>>> Justin.
>>
>> I saw a similar effect on a P5 board that could
>> only cache 64MB of memory a long time ago.
>> Putting more memory into it made the machine slower
>> and e.g. made the sym2 driver giving up at initialization.
>> Maybe it's a modern reincarnation of the problem?
>>
>> Best regards,
>> Zolt?n B?sz?rm?nyi
>>
>
> I see, so Intel 965 motherboards do not work with 8GB of memory? Or is this
> a Linux issue?
>
> I have an Intel Case ID open 225446 but so far we have not gotten anywhere
> with this problem. Currently I have 8GB in the machine and boot with
> mem=4096M. Was there any type of fix? Any recommendations as to what I can
> do? Continue to speak with Intel? Or perhaps someone with more knowledge of
> the kernel and chime in as to what exactly is happening here?
>
> Justin.
Adding Intel to CC list.