Re: dbench regression in 2.6

[Hans Reiser <reiser@namesys.com>]

Steven Pratt wrote:

> Mike Fedyk wrote:
>
>> On Thu, Sep 04, 2003 at 09:23:42AM -0500, Steven Pratt wrote:
>>  
>>
>>> Vladimir Saveliev wrote:
>>>
>>>   
>>>
>>>> Hi
>>>>
>>>> On Wednesday 03 September 2003 23:04, Hans Reiser wrote:
>>>>
>>>>     
>>>>
>>>>> Steven Pratt wrote:
>>>>>
>>>>>       
>>>>>
>>>>>> Is anyone looking into the dbench multitheaded regression in 2.6 
>>>>>> that I reported here a couple of weeks ago?   
>>>>>>         
>>>>>
>>>> Sorry, I was unable to find your report in mail archives. Could 
>>>> you, please, remind what is the problem?
>>>>
>>>> I don't see any change in the
>>>>     
>>>>
>>>>>> latest trees.
>>>>>>
>>>>>>   
>>>>>>         
>>>>>
>>> The problem showed up in 2.6.0-test1, and every kernel since.  The 
>>> problem is that from 2.5.65 (earliest data I have) to 2.5.69 dbench 
>>> on reiserfs with 16 clients got a throughput of ~200MB/sec.  In 
>>> 2.5.70 through 2.5.75 the score went up to ~280MB/sec, a good 
>>> thing.  But in 2.6.0-test1 the throughput dropped to below 50 
>>> MB/sec.  Since then it has risen slightly but still at only around 
>>> 60MB/sec.  Single client dbench showed similar, although much less 
>>> dramatic changes.  No other file system exhibited a change in the 
>>> 2.6.0-test1 kernel so this seems to be unique to reiserfs.
>>>   
>>
>>
>> Did anything change in the testing at all?  Can you try again with your
>> current software versions on 2.5.75, and reproduce the higher speeds?
>>  
>>
> No, nothing changed in the test setup.  Same dbench, same disk, same 
> distro, just different kernel.
>
>> Check the diffstat for the test1 release and see if there are any 
>> reiserfs
>> changes...
>>
> I believe that Oleg already said there were no changes that look like 
> they would have caused this.  More likely the behavior of something 
> reiser is using changed which is having a bad effect on resierfs.
>
> Steve
>
>
>
Vs discovered we are sleeping more in test0, and he is debugging the 
sleepometer so he can find out where (2.6.0 broke the sleepometer it seems).

-- 
Hans