MAP_SYNC destroys performance

[chloe-alverti]

Hi!

I am running rocksdb on a ext4 dax system in kernel 5.1.
I am testing it with YCSB workloads, and I enable dcpmm wal.
I noticed that the MAP_SYNC flag destroys scalability due to ext4 journaling overheads, and the overall performance is worse than using default rocksdb.

Has anyone else experience this?
Is this expected?

Best Regards,
Chloe

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Expected behavior

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