JFFS2-Summary support for u-boot
Hi *,
please feel free to correct me if I tell sh**:
As far as I was told, bad JFFS2 boot performance of u-boot is result of not supporting summary. (Because there is no JFFS2 but only JFFS support?)
So my question:
Has anybody done or is planning in next time (~weeks) to add summary support for u-boot JFFS2? We need a file system on 32MB NOR flash with wear leveling and acceptable boot time. Ubi is currently not supported for NOR, JFFS2 slow, ... :-(
TIA
Kind Regards,
M.Lawnick
Quoted 5 lines · Michael Lawnick
Hi *,
please feel free to correct me if I tell sh**:
As far as I was told, bad JFFS2 boot performance of u-boot is result of not supporting summary. (Because there is no JFFS2 but only JFFS support?)
It is not missing SUMMARY, it is excessive scanning of empty flash blocks. Look at jffs2/scan.c, it only scan the first 4KB or before declaring the block empty.
Jocke
Quoted 11 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Quoted 5 lines · Michael Lawnick
Hi *,
please feel free to correct me if I tell sh**:
As far as I was told, bad JFFS2 boot performance of u-boot is result of not supporting summary. (Because there is no JFFS2 but only JFFS support?)It is not missing SUMMARY, it is excessive scanning of empty flash blocks. Look at
jffs2/scan.c, it only scan the first 4KB or before declaring the block empty.
Ok, did I get you correct:
The performance difference between u-boot and linux is based on skipping senseless scans of empty blocks?
I've taken a little look into scan.c
The comment "The code lacks more or less any comment, and is still arcane and difficult to read in places." doesn't make me happy.
Has anybody tried to (and succeeded in) speed up u-boot?
Michael
Quoted 14 lines · Michael Lawnick
Quoted 11 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Quoted 5 lines · Michael Lawnick
Hi *,
please feel free to correct me if I tell sh**:
As far as I was told, bad JFFS2 boot performance of u-boot is result of not supporting summary. (Because there is no JFFS2 but only JFFS support?)It is not missing SUMMARY, it is excessive scanning of empty flash blocks. Look at
jffs2/scan.c, it only scan the first 4KB or before declaring the block empty.
Quoted 8 lines
Ok, did I get you correct:
The performance difference between u-boot and linux is based on skipping senseless scans of empty blocks?
I've taken a little look intoscan.c
The comment "The code lacks more or less any comment, and is still arcane and difficult to read in places." doesn't make me happy.Has anybody tried to (and succeeded in) speed up u-boot?
Yes, there was an attempt some time ago(months or a year, dunno) where someone had improved scanning dramatically, patch was posted to the u-boot list. Can't remember who though.
Jocke
Quoted 5 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Quoted 1 line
Has anybody tried to (and succeeded in) speed up u-boot?
Yes, there was an attempt some time
ago(months or a year, dunno)where someone had improved scanning dramatically, patch was posted to the u-boot list. Can't remember who though.
Seems to be the thread 'jffs2 fsload - SOLVED.' from 12 Jan 03:14 Dan Merillat. As I've looke into the patch, it seems not to have found its way into u-boot. Any(body any) idea why?
Michael
Quoted 10 lines · Michael Lawnick
Quoted 5 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Quoted 1 line
Has anybody tried to (and succeeded in) speed up u-boot?
Yes, there was an attempt some time
ago(months or a year, dunno)where someone had improved scanning dramatically, patch was posted to the u-boot list. Can't remember who though.Seems to be the thread 'jffs2 fsload - SOLVED.' from 12 Jan 03:14 Dan Merillat. As I've looke into the patch, it seems not to have found its way into u-boot.
Can't remember, possibly it was a hack.
Jocke
Quoted 2 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Can't remember, possibly it was a hack.
Seems so. I tried to put it in my 1.3.3, but 'ls' never returns :-(
So I will wait for Detlev Zundel.
Michael
Hi Michael,
Quoted 7 lines
Quoted 2 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Can't remember, possibly it was a hack.
Seems so. I tried to put it in my 1.3.3, but 'ls' never returns :-(
So I will wait for Detlev Zundel.
Actually someone doing the development for DENX will post the code, but it will not be me ;)
The code should hit the mailing list any day now. The speed improvements are pretty drastic, although dependant on the actual file system. Improvements by factors of 4 have been measured however...
Cheers
Detlev
Signature · 6 lines
"The number you have dialed is imaginary. Please rotate your phone 90 degrees and try again." -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de
Hi Michael,
Quoted 14 lines
Quoted 11 lines · Joakim Tjernlund <joakim.tjernlund <at> transmode.se> writes:
Quoted 5 lines · Michael Lawnick
Hi *,
please feel free to correct me if I tell sh**:
As far as I was told, bad JFFS2 boot performance of u-boot is result of not supporting summary. (Because there is no JFFS2 but only JFFS support?)It is not missing SUMMARY, it is excessive scanning of empty flash blocks. Look at
jffs2/scan.c, it only scan the first 4KB or before declaring the block empty.
Quoted 8 lines
Ok, did I get you correct:
The performance difference between u-boot and linux is based on skipping senseless scans of empty blocks?
I've taken a little look intoscan.c
The comment "The code lacks more or less any comment, and is still arcane and difficult to read in places." doesn't make me happy.Has anybody tried to (and succeeded in) speed up u-boot?
We are currently working on such a speedup bringing U-Boot up to par with Linux. I am confident that we can post our results in the next week.
Cheers
Detlev
PS: Wow, message-mode in Emacs wants a confirmation sending an email to
you as your address looks bogus ;)
Signature · 5 lines
Emacs is the way to purify your soul using garbage collection. -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de
Quoted 6 lines · Detlev Zundel
Quoted 1 line
Has anybody tried to (and succeeded in) speed up u-boot?
We are currently working on such a speedup bringing U-Boot up to par with Linux. I am confident that we can post our results in the next week.
Sounds promising!
Quoted 3 lines
PS: Wow, message-mode in Emacs wants a confirmation sending an email to
you as your address looks bogus ;)
Address is valid and in use. This nospam_ kept away spam for some time. Seems some filters sorted it out, others removed it.
Michael