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CMU-SAFARI / MQSim

MQSim is a fast and accurate simulator modeling the performance of modern multi-queue (MQ) SSDs as well as traditional SATA based SSDs. MQSim faithfully models new high-bandwidth protocol implementations, steady-state SSD conditions, and the full end-to-end latency of requests in modern SSDs. It is described in detail in the FAST 2018 paper by Arash Tavakkol et al., "MQSim: A Framework for Enabling Realistic Studies of Modern Multi-Queue SSD Devices" (https://people.inf.ethz.ch/omutlu/pub/MQSim-SSD-simulation-framework_fast18.pdf)
https://people.inf.ethz.ch/omutlu/pub/MQSim-SSD-simulation-framework_fast18.pdf
MIT License
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Questions about Hybrid FTL #32

Open SAM-ZY-2019 opened 4 years ago

SAM-ZY-2019 commented 4 years ago

The hybrid FTL doesn't work properly. I wrote a write amount count monitor to print out in-byte writes of host and SSD.

PAGE_LEVEL FTL:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Host: WriteAmount=930493 LBAs. (512 bytes/sector)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Host: WriteAmount=58155.8 LPAs. (8192 bytes/page)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Host: WriteAmount=476412416 bytes.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SSD:  WriteAmount=7622598656 bytes.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SSD:  Page_Capacity=8192 bytes.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SSD:  WriteAmount=930493 PPAs. (8192 bytes/page)
Flow Host.IO_Flow.Synth.No_0 - total requests generated: 930493 total requests serviced:930493
WAF is around 16, which make sense.

HYBRID FTL MODE

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Host: WriteAmount=2 LBAs. (512 bytes/sector)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Host: WriteAmount=0.125 LPAs. (8192 bytes/page)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Host: WriteAmount=0 bytes.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SSD:  WriteAmount=0 bytes.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SSD:  Page_Capacity=8192 bytes.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SSD:  WriteAmount=0 PPAs. (8192 bytes/page)
Flow Host.IO_Flow.Synth.No_0 - total requests generated: 2 total requests serviced:0

I even tried the original MQSim's sample traces, as long as I set the SSD to hybrid FTL mode, it doesn't write PPAs at all.