Linux 4.12 I/O Scheduler Tests With A HDD & SSD

[phoronix]

Phoronix: Linux 4.12 I/O Scheduler Tests With A HDD & SSD

Earlier in the Linux 4.12 cycle I delivered a number of I/O scheduler benchmarks from a solid-state drive while for this article are some fresh I/O scheduler tests using a slower SSD as well as a conventional HDD. Schedulers tested were CFQ, Noop, deadline, MQ None, MQ Kyber, MQ BFQ, and MQ Deadline.

http://www.phoronix.com/vr.php?view=24887

[enihcam]

Looks like BFQ is the best for those who dont want to wait for disk operations. e.g. desktop users.

[Shnatsel]

Huh. I knew BFQ was latency-oriented but I did not expect it to be that bad at throughput.

Perhaps something about multi-queue mode not being handled properly? I would really like an explanation.

[boxie]

Where is the CFQ result on the last graph (the postgres benchmark) ?

[boxie]

Huh. I knew BFQ was latency-oriented but I did not expect it to be that bad at throughput.

Perhaps something about multi-queue mode not being handled properly? I would really like an explanation.

If you are constantly context switching then you will suffer in terms of total work throughput - but you may appease some managers (wait, are we still talking about schedulers here?)

[starshipeleven]

Huh. I knew BFQ was latency-oriented but I did not expect it to be that bad at throughput.

Perhaps something about multi-queue mode not being handled properly? I would really like an explanation.

Or there was some other application(s) which BFQ gave higher priority during the tests.

This sounds kinda strange though, in my tests I didn't get this massive performance hits. Although I did much more mundane things, without the test suite.

[davidbepo]

also blk-mq seems to have a bug that hurts anything multiqueue

[GrayShade]

Michael This probably comes often when people test BFQ, but can you try running the tests with the low_latency parameter disabled?

[Fry-kun]

What's up with IOzone graph? Since when is SSD slower than HDD?

[davidbepo]

What's up with IOzone graph? Since when is SSD slower than HDD?

didn't notice, WTF IMPOSIBURU!