Hi Artem OneNAND can support for full block read also in sync burst block read mode ,so why u want to limit bulk read only for 4 pages , with sync burst enable u can read max 64 pages. so in place of max 4 pages , u can set max to 64 it will be improve performance if sync burst mode is upported. Rgs Amit ----- Original Message ----- From: "Artem Bityutskiy" <dedekind@xxxxxxxxxxxxx> To: <linux-fsdevel@xxxxxxxxxxxxxxx> Cc: <linux-mtd@xxxxxxxxxxxxxxxxxxx>; "Adrian Hunter" <ext-adrian.hunter@xxxxxxxxx>; <linux-kernel@xxxxxxxxxxxxxxx> Sent: Tuesday, September 30, 2008 2:48 PM Subject: What is in ubifs-2.6.git > Hi, > > here is the stuff we have scheduled for 2.6.28. The > patches > contains various small fixes and cleanups, but there is > something > interesting as well. > > The first interesting thing is new "bulk read" > functionality. The > idea is that many NAND flashes support "bulk read" in some > form. > For example, OneNAND has "read while load" feature, which > allows > reading consecutive NAND pages faster than reading them > one-by-one. > > So we've made UBIFS benefit from this feature and > introduced new > "bulk_read" mount option. With this option enabled UBIFS > reads files > a little ahead if the file data sits in consecutive > physical > addresses. For example, if user-space asks to read page > zero of a > file, and page 0-4 are in consecutive flash addressed, > UBIFS reads > pages 0-4 and populates them to the Page Cache. > > Note, this is disabled by default and UBIFS has to be > explicitly > mounted mounted with "bulk_read" option. The reason for > this is > that we consider this feature as experimental so far. > > Note, UBIFS does not use VFS read-ahead and actually > explicitly > disables it. This is because MTD is synchronous and all > I/O is > done synchronously, so read-ahead actually slows things > down for > UBIFS, instead of improving them. So the "bulk read" > feature is > basically internal UBIFS read-ahead implementation. > > We are able to gain 4-5MiB/s of read speed on OneNAND with > bulk > read enabled. > > The second interesting thing is new "no_chk_data_crc" > mount option > which disables data CRC32 checking. > > UBIFS always checks CRC of everything it reads from flash > by default. > On ARM platform this results in ~30% of total CPU usage in > profiles, > which is quite high. But many modern flashes are very > reliable > (e.g., OneNAND), and one does not need that level of > protection. > So now it is possible to disable CRC checking for _data_. > However: > > * internal indexing information CRC is always checked; > * when replaying the journal, data CRC is always checked; > * on write, CRC is always calculated. > > With this mount option we are able to gain another > 4-5MiB/s of read > speed on OneNAND. And together with bulk-read, the read > speed becomes > ~10MiB/s faster. > > Adrian Hunter (11): > UBIFS: add bulk-read facility > UBIFS: add no_chk_data_crc mount option > UBIFS: improve znode splitting rules > UBIFS: correct key comparison > UBIFS: ensure data read beyond i_size is zeroed out > correctly > UBIFS: allow for sync_fs when read-only > UBIFS: improve garbage collection > UBIFS: fix bulk-read handling uptodate pages > UBIFS: add more debugging messages for LPT > UBIFS: correct condition to eliminate unecessary > assignment > UBIFS: check buffer length when scanning for LPT > nodes > > Artem Bityutskiy (9): > UBIFS: add a print, fix comments and more minor stuff > UBIFS: inline one-line functions > UBIFS: check data CRC when in error state > UBIFS: use bit-fields when possible > UBIFS: fix races in bit-fields > UBIFS: fix commentary > UBIFS: update dbg_dump_inode > UBIFS: correct comment for commit_on_unmount > UBIFS: commit on sync_fs > > Hirofumi Nakagawa (1): > UBIFS: remove unneeded unlikely() > > Julien Brunel (1): > UBIFS: use an IS_ERR test rather than a NULL test > > Documentation/filesystems/ubifs.txt | 9 + > fs/ubifs/budget.c | 26 ++-- > fs/ubifs/debug.c | 79 +++++++-- > fs/ubifs/debug.h | 6 + > fs/ubifs/file.c | 260 > ++++++++++++++++++++++++++ > fs/ubifs/find.c | 4 +- > fs/ubifs/gc.c | 90 ++++++++-- > fs/ubifs/io.c | 12 +- > fs/ubifs/key.h | 22 ++- > fs/ubifs/lprops.c | 34 +---- > fs/ubifs/lpt.c | 3 +- > fs/ubifs/lpt_commit.c | 187 > ++++++++++++++++++- > fs/ubifs/misc.h | 27 +++ > fs/ubifs/scan.c | 2 +- > fs/ubifs/super.c | 109 +++++++++-- > fs/ubifs/tnc.c | 345 > ++++++++++++++++++++++++++++++++--- > fs/ubifs/tnc_misc.c | 4 +- > fs/ubifs/ubifs-media.h | 1 - > fs/ubifs/ubifs.h | 85 +++++++-- > fs/ubifs/xattr.c | 2 +- > 20 files changed, 1149 insertions(+), 158 deletions(-) > > -- > Best regards, > Artem Bityutskiy (?龜???克龜橘 ????劇) > > -------------------------------------------------------------------------------- > ______________________________________________________ > Linux MTD discussion mailing list > http://lists.infradead.org/mailman/listinfo/linux-mtd/ > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
