9373759d13
Original commit "7090 zfs should improve allocation order" declares alloc queue sorted by time and offset. But in practice io_offset is always zero, so sorting happened only by time, while order of writes with equal time was completely random. On Illumos this did not affected much thanks to using high resolution timestamps. On FreeBSD due to using much faster but low resolution timestamps it caused bad data placement on disks, affecting further read performance. This change switches zio_timestamp_compare() from comparing uninitialized io_offset to really populated io_bookmark values. I haven't decided yet what to do with timestampts, but on simple tests this change gives the same peformance results by just making code to work as declared. MFC after: 1 week |
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| boot/zfs | ||
| compat/opensolaris | ||
| contrib/opensolaris | ||
| dev | ||