svn commit: r297633 - in head: sys/cddl/contrib/opensolaris/uts/common/fs/zfs sys/fs/ext2fs sys/kern sys/sys sys/ufs/ffs sys/ufs/ufs sys/vm usr.bin/rctl

[Edward Tomasz Napierala]

On 0407T1632, Slawa Olhovchenkov wrote:
> On Thu, Apr 07, 2016 at 04:23:25AM +0000, Edward Tomasz Napierala wrote:
> 
> > Author: trasz
> > Date: Thu Apr  7 04:23:25 2016
> > New Revision: 297633
> > URL: https://svnweb.freebsd.org/changeset/base/297633
> > 
> > Log:
> >   Add four new RCTL resources - readbps, readiops, writebps and writeiops,
> >   for limiting disk (actually filesystem) IO.
> >   
> >   Note that in some cases these limits are not quite precise. It's ok,
> >   as long as it's within some reasonable bounds.
> >   
> >   Testing - and review of the code, in particular the VFS and VM parts - is
> >   very welcome.
> 
> How you calculate iops for sequential IOs? As distinc IOPS or merged?
> 
> I.e. readin 1 sector from offset 100 and immediately reading 1 sectro
> from offset 101 accounting as 2IOPS or as 1IOPS?

Probably one, due to taking readahead into account.  But it depends
on the filesystem, and is only an best-effort estimation.