Re: Slow OS calls on one chip type
On 16/04/2010 14:08, Alexandre Marini wrote:
> Mr. Neil,
> Are you sure it's all the same???
> Isn't any difference between the disks configuration???
> (Ie: raw devices on old one, and cooked files on this new one???)
>
> That's just a guess, but it seems you're having some troubles on this
> section, isn't it ?
>
> How are your storage system architecture?
>
> Regards.
>
> Alexandre Marini
>
> Tecnologia da Informa''o - DBA
>
> SEFAZ-MS / SGI-UIMP / Sistemas IBM-Informix
>
> See you at the 2010 IIUG Informix Conference
> April 25-28, 2010
> Overland Park (Kansas City), KS
> www.iiug.org/conf
>
> <http://www.iiug.org>;
>
>
>
> Neil Truby escreveu:
>> IDS 11.5FC6 on RHEL 5.3
>>
>> Here's a starange one. When running SQL which interacts with OS to output
>> messages, it's very, very much slower at a new customer site than it is at
>> our own or others. The difference seems to be the AMD processors the
>> customer has (we have Intel) - the OS and IDS versions are identical.
>>
>> Here's a a simple test case. Here's some SQL, which echoes out the message
>> "Hello World" 64 times:
>> !echo "Hello World"
>> !echo "Hello World"
>> !echo "Hello World"
>> !echo "Hello World"
>> ...
>> !echo "Hello World"
>>
>> Run it on the AMD server:
>>
>> informix@db-1<qa1>:ardenta]$ time dbaccess sysmaster< crap5.sql
>>
>> Database selected.
>>
>> Hello World
>> ...
>> Hello World
>>
>> Database closed.
>>
>>
>> real 0m7.776s
>> user 0m0.016s
>> sys 0m0.049s
>>
>> Run it on an Intel server, same IDS version etc:
>>
>> Hello World
>> ...
>> Hello World
>>
>> Database closed.
>>
>> real 0m0.580s
>> user 0m0.005s
>> sys 0m0.037s
>>
>> 12 times as slow on AMD. We noticed it when trunning some data load scripts
>> which outputs thousands of progress messages, and went from 10m at home to
>> 50m on the client's (far superior) hardware. Of course we could just omit
>> the statements, but I am worried that this may be part of a bigger issue.
>>
>> IBM PMR 85722,019,866 refers.
>>
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>>
>>
Well, why not do this (as previously posted, but removing the database connection) :
strace -o slow1.out -c -f dbaccess - slow1
where slow1 contains your 64 !echo "Hello World"
Also, just try it on the actual machine rather than via ssh