Suppose that you have small directories, such that the time to do linear
searching within the directory is not significant.
Suppose that you have a tendency to access files in readdir() order, and
having files laid out in an order that is the same as the directory
order is performance valuable.
Suppose that you create files too slowly for allocate on flush to fix
this problem, and access them too soon for the repacker to fix this problem.
In that case, ordering both directory entries and file bodies in a first
created first ordered order is optimal.
How much work would it be to create a reiser4 directory plugin to order
in creation time order? Could you do this by simply setting the hash
field always to zero for that plugin, and letting the duplicate key code
handle things? If it is trivial to do, it might be useful. Especially
for the analysis of the performance of our algorithms on various benchmarks.
Are you ready to work on implementing file body key assignment in order
of directory entries?
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Hans
