New: mpt3sas / LSI SAS 9300-8i write performance bottleneck
https://bugzilla.kernel.org/show_bug.cgi?id=70851
Bug ID: 70851
Summary: mpt3sas / LSI SAS 9300-8i write performance bottleneck
Product: SCSI Drivers
Version: 2.5
Kernel Version: 3.12.9-201.fc19.x86_64
Hardware: x86-64
OS: Linux
Tree: Mainline
Status: NEW
Severity: high
Priority: P1
Component: Other
Assignee: [email protected]
Reporter: [email protected]
Regression: NoDescription of problem:
LSI SAS 9300-8i write performance too slow
(whilst read performance is just fine).
Version-Release number of selected component (if applicable):
Kernel 3.12.9-201.fc19.x86_64
How reproducible:
Always
Steps to Reproduce:
1. attach 3 SSDs to adapter
2. create striped mapped device (e.g. using LVM)
3. dd of=/dev/$TheStripedDevice oflag=direct if=/dev/zero iflag=fullblock bs=2G count=1
Actual results:
Single threaded read performance is as expected, ie. 3 SSDs (3 * Samsung 840EVO
1TB) with per drive sustained read throughput of 540MB/s lead to ~1.6GB/s on a
striped logical volume (all 3 attached to one SFF-8643 port of the HBA via a 1:4 mSAS to SAS cable).
Write performance on the same striped LV as in "Steps to Reproduce" (1 thread) maxes out at ~750MB/s as opposed to the maximum write throughput of ~490MB/s on each of the 3 SSDs written one by one
Measured:
- ~490MB/s writing (1 thread) to the individual SSDs one by one
- ~750MB/s writing (1 thread) to all 3 SSDs in parallel via the striped LV
- ~1GB/s (3 * ~340MB/s) writing (3 threads) to all 3 SSDs in parallel; ie. better than the striped LV write performance
Expected results:
Expecting >1.4GB/s write maximum on the striped LV written single threaded.
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[Bug 70851] mpt3sas / LSI SAS 9300-8i write performance bottleneck
https://bugzilla.kernel.org/show_bug.cgi?id=70851
Heinz Mauelshagen <[email protected]> changed:
What |Removed |Added
----------------------------------------------------------------------------
Tree|Mainline |Fedora
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[Bug 70851] mpt3sas / LSI SAS 9300-8i write performance bottleneck
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=70851
--- Comment #1 from Heinz Mauelshagen <[email protected]> --- The same with 3.13.3-201.fc20.x86_64
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