On Fri, Feb 14, 2025 at 07:41:45AM +0100, hch wrote: > On Thu, Feb 13, 2025 at 01:03:31PM +0000, Hans Holmberg wrote: > > That sounds like good idea. Christoph: could you fold in the above lines > > into the commit message for the next iteration of the series? > > It needed a bit of editing to fit into the commit messages. This is what > I have now, let me know if this is ok: > > fs: support write life time based data placement > > 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. > > This improvement in data placement efficiency reduces the number of > blocks requiring relocation by GC, and thus decreases overall write > amplification. The impact on performance varies depending on how full > the file system is. > > For RocksDB using leveled compaction, the lifetime hints can improve > throughput for overwrite workloads at 80% file system utilization by > ~10%, but for lower file system utilization there won't be as much > benefit in application performance as there is less need for garbage > collection to start with. > > Lifetime hints can be disabled using the nolifetime mount option. Perfect! --D
