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Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] Allocate mutiple clusters for
Re: [Qemu-block] [Qemu-devel] [PATCH 0/2] Allocate mutiple clusters for VMDK I/O
Tue, 21 Mar 2017 07:51:46 +0000
On Sat, Mar 11, 2017 at 11:54 AM, Ashijeet Acharya
> This series optimizes the I/O performance of VMDK driver.
> Patch 1 makes the VMDK driver to allocate multiple clusters at once. Earlier
> it used to allocate cluster by cluster which slowed down its performance to a
> great extent.
> Patch 2 changes the metadata update code to update the L2 tables for multiple
> clusters at once.
This patch series is a performance optimization. Benchmark results
are required to justify optimizations. Please include performance
results in the next revision.
A popular disk I/O benchmarking is fio (https://github.com/axboe/fio).
I suggest a write-heavy workload with a large block size:
$ cat fio.job
$ for i in 1 2 3 4 5; do fio --output=fio-$i.txt fio.job; done #
WARNING: overwrites /dev/vdb
It's good practice to run the benchmark several times because there is
usually some variation between runs. This allows you to check that
the variance is within a reasonable range (5-10% on a normal machine
that hasn't been specially prepared for benchmarking).