On Wed, Feb 12, 2025 at 01:29:21PM +0000, Hans Holmberg wrote: > On 12/02/2025 01:27, Darrick J. Wong wrote: > > On Thu, Feb 06, 2025 at 07:44:55AM +0100, Christoph Hellwig wrote: > >> From: Hans Holmberg <hans.holmberg@xxxxxxx> > >> > >> Add a file write life time data placement allocation scheme that aims to > >> minimize fragmentation and thereby to do two things: > >> > >> a) separate file data to different zones when possible. > >> b) colocate file data of similar life times when feasible. > >> > >> To get best results, average file sizes should align with the zone > >> capacity that is reported through the XFS_IOC_FSGEOMETRY ioctl. > >> > >> For RocksDB using leveled compaction, the lifetime hints can improve > >> throughput for overwrite workloads at 80% file system utilization by > >> ~10%. > > > > The code changes look mostly ok, but how does it do at 40% utilization? > > 99%? Does it reduce the amount of relocation work that the gc must do? > > The improvement in data placement efficiency will always be there, > reducing the number of blocks requiring relocation by GC, but the impact > on performance varies depending on how full the file system is. > > At 40% utilization there is almost no garbage collection going on, so the > impact on throughput is not significant. At 99% the effects of better > data placement should be higher. <nod> Would you mind pasting that into the commit message? --D > Cheers, > Hans >
