Hi
I have few suggestions for sreadahead, I hope this list is the proper
place for them.

* earlied versions of sreadahead used to put files under /etc, while
version 1.0 uses /var. I find /etc to be more convenient, since I use
a separate /var partition, and it is not yet mounted when
rc.early.local is invoked (i.e. where I would like to start
sreadahead)
* use posix_fadvise(fd,off,len,POSIX_FADV_WILLNEED) instead of
readahead(fs,off,len): posix_fadvise is non-blocking until there is
room in the queue, so you can get rid of multithreading, and it will
better interact with the block layer, allowing it to reorder more
requests according to disk placement.
* export a plain file list of the files that are opened during boot.
this list can be used by external script to optimize on-disk file
placement for rotational disks.
* give an option to skip readahead of large contiguous blocks.This
improves rotational disk performance when the disk is the bottleneck,
since we prefetch all random accesses, that normally incur in high
latency, and let the processes complete their sequential reads, that
are faster, only when needed, with less contention.

Corrado

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