Messages in this thread | | | Date | Wed, 24 Sep 1997 09:33:28 -0400 (EDT) | From | linux kernel account <> | Subject | Re: New feature |
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It's a mount option now. noatime it is in 2.0.31 and 2.1.x
On Tue, 23 Sep 1997, Arthur Jerijian wrote:
> Sounds like the ls -lR operation updated the atimes of every single > directory entry starting from /, and perhaps all the files in all the > directories as well. The sync command writes these atimes back to > the disk, which is why it takes so long. > > There used to be a patch that disabled the use of atime altogether. Is > this patch still around? Did it make it to 2.1? > > Thanks! > --Arthur > > On Tue, 23 Sep 1997, Richard B. Johnson wrote: > > > > > Possible bug or feature in V2.1.55 with pre-patch-2.1.56B (which?). > > > > o Boot machine with init=/bin/bash > > > > o Mount the root file-system. > > `mount -n -o remount /` > > > > o Mount /proc if you want. Do not start /sbin/update. > > > > o Perform `ls -R /`. The hard disk will be active. > > > > o If you have plenty of RAM, the second time you perform `ls -R /` > > no disk activity will occur because the whole directory structure > > is is RAM. This is nice. This is how it should be. > > > > o Now perform `sync`. Every directory entry will be updated, causing > > an enormonous amount of wasted CPU cycles and disk activity! > > Sync should have done nothing. The disk was never written. > > If you execute `ls -R /`, the entire directory structure is again > > read from the physical media. Not nice. > > > > o Now, if you start /sbin/update, you will see the same problem as > > update calls sync() every so-often. Every time sync() is called > > by update, the entire directory structure that exists in the new > > dcache is either read from, or written to, the physical disk! > > > > o This undoes all the good work that the new dcache code did. > > > > Cheers, > > DJ > > Richard B. Johnson > > Analogic Corporation > > Penguin : Linux version 2.1.55 on an i586 machine (66.15 BogoMips). > > Warning : It's hard to stay on the trailing edge of technology. > > Linux : Engineering tool > > Spam : sync@localhost, daemon@loghost > > > > >
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