Questions about Hybrid FTL
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SAM-ZY-2019 commented
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.