Thank you again for running all of these tests on your various hardware configurations. I was not aware of the convention that the commented example in the config file is expected to match the default value, so I was actually trying to show what to use if you didn't want the default, but I am happy to update the patch so the comment matches the default. Beyond that, I am unsure what the next steps are for this proposal.
So here is the last set of benchmark results, this time from ext4 on a small SATA-based RAID (3 x 7.2k). As before, I'm only attaching PDFs with the simple charts, full results are available in the git repository [1]. Overall the numbers are rather boring, with almost no difference between the two setups.
That being said, I'm not opposed to introducing the GUC. I'm not going to pretend my tests represents all possible HW configs and workloads, and I have no trouble believing that it may be quite beneficial in some cases.
The one comment about the code is that we usually use the actual default value in the config sample. But the patch does this:
