On Wed, Mar 25, 2009 at 04:23:08PM -0700, Linus Torvalds wrote:This tuning logic is the core of what Josef Bacik did for the transaction batching code for ext4....
On Wed, 25 Mar 2009, Theodore Tso wrote:
How are you going to tell the kernel that the RAID array can write 100MB/s?The problem being that unlike the ratio, there's no sane default value that you can at least argue is not _entirely_ pointless.Well, if the maximum time that someone wants to wait for an fsync() to
return is one second, and the RAID array can write 100MB/sec
The kernel has no idea.
Not at boot up, but after it's been using the RAID array for a little
while it could...
Bron (... imagining a tunable "max_fsync_wait_target_centisecs = 100" which caused the kernel to notice how long flushes were taking
and tune its buffer sizes to be approximately right over time )