Author Topic: New tRAID performance features: SIMT & Write Chatter  (Read 1508 times)

Offline Brahim

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New tRAID performance features: SIMT & Write Chatter
« on: November 26, 2017, 10:04:47 am »
For those that paid attention, you have noticed new configuration options in the latest releases.
SIMT: Windows and Linux
Write Chatter: Linux

SIMT: Single instruction, multiple threads
https://en.wikipedia.org/wiki/Single_instruction,_multiple_threads
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Advanced RAID Performance Scaling through SIMT (Single Instruction, Multiple Threads).
SIMT results in higher CPU usage in order to achieve higher performance. So, it should be disabled (set to 0) or scaled down (less than the optimal value) if your system's priorities call for low RAID CPU usage.
The optimal SIMT value is the number of virtual cores in the system (e.g., 8 if single quad-core CPU with HT)
Increasing SIMT past the optimal value can result increase performance but only at a marginal rate. A too high SIMT value will actually degrade performance (typically, anything passed double the optimal value).

Write Chatter
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Write chatter is a proprietary technology we have developed to improve IOPS and throughput on low latency devices.
It only works when all devices in the array are low-latency devices (typically SSDs) and has the opposite effect on high-latency devices (low RPM HDDs).
Again, do not bother with this feature unless you have disks with really fast access time as it will negatively affect your RAID performance otherwise.

Please post your findings when enabling these new features.