FlaSim
목차 |
FlaSim : A FTL & Flash Memoty Emulator on Linux
1. Download - Binary codes
2. User's manual (Korean) - FlaSim/Implementation Notes
3. Environment
- Linux 2.6.20 or above
- GCC 4.2.4
4. How to execute FlaSim
- 1) Create a directory /home/flasim/vol
# mkdir /home/flasim/vol
- 2) Create file /home/flasim/vol/nfdda.vol
# mkvol -f small -path /home/flasim/vol -s 512 -p 1000 a
- 3) Create and initialize the flash volume
# mkftl.log /home/flasim/vol/nfdda.vol 3
- 4) Load kernel modules for NAND flash emulator
# insmod klib.ko # insmod fdevmgr.ko # insmod small.ko # insmod log-small.ko # insmod nfdd.ko ndevices=1 volpath=/home/flasim/vol
- 5) Check the kernel modules
# cat /proc/fdevmgr
- 6) Format the FTL volume
# mkfs.ext2 /dev/nfdda
- 7) Mount the ext2 file system on directory a
# mount /dev/nfdda a
5. You can get statistics of Flasim through proc files.
# cat /proc/nfdd/nfdda/vol # cat /proc/nfdd/nfdda/ftl # cat /proc/nfdd/nfdda/flash
How to use nfdd
How to create a volume
You can create a volume using mkvol.
This tool create a file in the directory, and it will be treated as a flash memory as
/dev/nfdda device.
Usage: mkvol [-h] (display meta information)
[-f large|small|small-ecc] (flash memory type)
[-path volume_path] (the path of the volume)
[-s sector_size] (physical sector size)
-p size (the number of blocks)
device_id (device id: a, b, etc)Example
# mkvol -f small -path /home/vol -s 512 -p 1000 a # mkvol -f large -path /home/vol -s 512 -p 2000 b # mkvol -f small-ecc -path /home/vol -s 512 -p 3000 c
FTL Initialization
In this section, the utilities to initialize a flash memory (volume) to specific FTL are describe.
FMAX
Each data block has a corresponding replacement block.
Usage: mkftl.fmax volume_name
Examples:
# mkftl.fmax /home/vol/nfdda.vol
Format FMAX applying SLB (it's experimental)
Usage: mkftl.fmax-slb volume_name SLB_size
Example : when setting the number of SLB as 101
# mkftl.fmax-slb /home/vol/nfdda.vol 101
Mitsubishi
Each block has spare space.
Usage: mkftl.mits volume_name no_spare
Example : when setting the number of spare space as 16 sectors
# mkftl.mits /home/swpark/vol/nfddb.vol 16
Format to use M-System applying SLB
Usage: mkftl.mits-slb volume_name no_spare SLB_size
Example : setting the number of spare space as 16, the number of SLB as 101
# mkftl.mits-slb /home/vol/nfddb.vol 16 101
Log block
There are several log blocks.
Usage: mkvol.log file no_log_blocks
Example : when setting the number of log blocks as 3
# mkvol.log /home/vol/nfddc.vol 3
Install Device drivers
klib, fdevmgr
# insmod klib.ko # insmod fdevmgr.ko
If you install fdevmgr, then file /proc/fdevmgr will be created.
You can verify the installed device drivers when you dump this file.
# cat /proc/fdevmgr 0 : e0c266f0, small 1 : e0c57b34, fmax-small
flash memory device driver
Currently supported types of flash memories
- small
- large
- small-ecc
If you want to load three device drivers, the instructions are as follows:
# insmod small.ko log_msg=0 - if you want to log, set the option as log_msg=1 or default option # insmod large.ko # insmod small-ecc.ko
FTL device dirver
Currently supported FTLs are as follows:
- fmax-small
- fmax-slb-small
- mits-large
- mits-small
- mits-slb-small
- log-small
- log-large
If you want install these device drivers, type like this
# insmod fmax-small.ko # insmod fmax-slb-small.ko # insmod mits-large.ko # insmod mits-small.ko # insmod mits-slb-small.ko # insmod log-small.ko # insmod log-large.ko
You can check the installation status when reading /proc/fdevmgr file.
nfdd device driver
This is how to load device drivers. The method in this section loads a volume in the directory
/home/vol. After that, a file /dev/nfdda will be created.
If you give the option as ndevices=2, then a file called /dev/nfddb will be
created.
Usage: insmod nfdd.ko ndevices=1 volpath=/home/vol
- When you want to load a new volume after installing
nfdddevice driver, you can do it as follows:
# echo "insvol b" > /proc/nfdd/command
- If you want to remove a volume during runtime, unmount the volume and type below instruction.
# echo "rmvol b" > /proc/nfdd/command
- When you install
nfdd, then a directory/proc/nfddis created.
# ls /proc/nfdd command nfdda status # cat /proc/nfdd/status volume path : /home/swpark/vol no device ftl flash psize lsize sector ------------------------------------------------------------- 0 nfdda fmax-small small 1000 499 512
- Directory contents of
/proc/nfdd/nfdda
# ls -l /proc/nfdd/nfdda total 0 -r--r--r-- 1 root root 0 2011-05-01 02:47 flash --w--w--w- 1 root root 0 2011-05-01 02:47 flash.type -r--r--r-- 1 root root 0 2011-05-01 02:47 ftl --w--w--w- 1 root root 0 2011-05-01 02:47 ftl.command -r--r--r-- 1 root root 0 2011-05-01 02:47 vol
- flash : display the status of flash memory
- flash.type : set the flash type
- ftl : display the status of FTL
- ftl.command : proc file to send a command to FTL
- vol : display the information of command transferred from File system to the FTL
- How to display the status information of flash memory
# cat /proc/nfdd/nfdda/flash
Device conf : []
Volume name : /home/swpark/vol/nfdda.vol
Log name : /home/swpark/vol/nfdda.log
Operations : e0c266f0
Company: Model:
tERASE: 0 tPROG: 0 tR: 0 tH2D: 0 tD2H: 0
The number of operation calls
load_page store_page erase_block get_from_register put_to_register
544444 135554 3013 524399 248943
The number of bytes transferred
reg2host host2reg time
971903 59225902 0
- How to display the status information of FTL
# cat /proc/nfdd/nfdda/ftl
flash:e0c1b000 ftl_operations:e0c57b34
merge: 715 smart merge:3166 no of fmax blocks:499 mirror util:59%
free_blk free_blk2 read_sectors write_sectors
383 999 129 20287
- How to display the I/O information of the File system (volume information)
# cat /proc/nfdd/nfdda/vol
Disk Number: 0 No. of Users: 1
Device Size: 15968 sectors (512 bytes/sector)
Volume Name: /home/swpark/vol/nfdda.vol
Log Name: /home/swpark/vol/nfdda.log
Thread Name: knfddad Request Queue: df81d830
gendisk: df694d80 workqueue: de182940
No. of function calls & transferred data:
read_call read_sect read_byte write_call write_sect write_byte request
129 864 442368 20287 89948 46053376 11733
nfdd_meta:
Magic: 179cd613-c0a5-4453-8924-1dc13b961bb9 type: 2
sector size: 512
No. blocks: PHYSICAL(1000) LOGICAL(499)
flash: small
ftl: fmax-smallHow to log
$ echo "print stat" > /proc/nfdd/nfdda/ftl.command $ echo "print map" > /proc/nfdd/nfdda/ftl.command $ echo "print all" > /proc/nfdd/nfdda/ftl.command
You can log the statistics by stat command. Command map is for writing the map information of the FTL and you can use it when you debug the device driver. all executes both commands stat and map.
If you want to write a specific message to log, write command as follows:
$ echo "echo this is message" > /proc/nfdd/nfdda/ftl.command
"# this is message" is written in the log.
How to change the strategy to select a victim in log block
This is for log block only.
$ echo "change algo UTIL" > /proc/nfdd/nfdda/ftl.command
- UTIL : select a victim of which utilization is the largest
- LFU, LRU : select a victim using LFU or LRU
Linux
- Download Ubuntu 8.04.4 LTS (Linux 2.6) - [1]
- FlaSim을 개발한 버전이므로 이 버전의 Linux를 설치하면 FlaSim 컴파일이 잘 된다.
