Re: mongo benchmark results

[Hans Reiser <reiser@namesys.com>]

David Dabbs wrote:

>At http://dabbs.net/reiser4/mongo.html I've posted some benchmarks from my
>aging but available test box. All numbers were generated with the Namesys
>mm7 snapshot. The "A.INFO_R4=new" are results from a reiser4 with modified
>comparison functions as well as znode_contains_key_strict(). So, here are my
>questions:
>
>Do these results appear consistent with others' recent benchmarking? 
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Increase file_size to 8k, and then we can compare.  This will reduce 
reiser4's space savings from 19% to 9%, but it will probably increase 
performance.

Your work had a remarkable effect on the create phase.  Very good work.  
I don't know why the impact was not larger for the stats phase.

Elena, please reproduce his results on our hardware.

>Should I be using particular mount options during benchmarking?
>I would think running mongo would be necessary to ensuring that reiser4 mods
>are 'safe,' but it is sufficient?
>Viz the prior question, is there a recommended test regimen or regression
>suite?
>
>
>I started to dig into mongo a bit and noticed that it does not appear to
>vary the file & dir _names_ it generates. Most appear to be ~7 characters
>long with a pattern of 'f' followed by some number. Isn't this a) atypical
>of file/dir name distribution and b) favorable to/biased towards the "short
>name" code? IOW, if R4_LARGE_KEYS is the default and all generated test file
>names' lengths < 15 characters,
>
You are encouraged to survey filesystems and supply a realistic filename 
generator.

In practice, most filenames are less than 15 characters. 

Another thing we need to do is add a file data generator that is based 
on slicing and dicing a linux kernel tarball, because we won't be able 
to do a good benchmark of the compression code until we do so.

> then the large file name code is not being
>covered or benchmarked. Perhaps I'm mixing apples and oranges (code coverage
>and benchmarking). 
>
>
>Just curious,
>
>David
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