25 lines
1004 B
Plaintext
25 lines
1004 B
Plaintext
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This application measures the software overhead of I/O submission
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and completion for both the SPDK NVMe driver and an AIO file handle.
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It runs a random read, queue depth = 1 workload to a single device,
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and captures TSC as follows:
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* Submission: capture TSC before and after the I/O submission
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call (SPDK or AIO).
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* Completion: capture TSC before and after the I/O completion
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check. Only record the TSC delta if the I/O completion check
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resulted in a completed I/O. Also use heuristics in the AIO
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case to account for time spent in interrupt handling outside
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of the actual I/O completion check.
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Usage:
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To test software overhead for a 4KB I/O over a 10 second period:
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SPDK: overhead -s 4096 -t 10
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AIO: overhead -s 4096 -t 10 /dev/nvme0n1
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Note that for the SPDK case, it will only use the first namespace
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on the first controller found by SPDK. If a different namespace is
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desired, attach controllers individually to the kernel NVMe driver
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to ensure they will not be enumerated by SPDK.
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