On 14-08-24 11:22 AM, [email protected] wrote: > On Sun, 24 Aug 2014 01:49:07 -0400, nick said: >> After searching through parts of the btrfs code and docs. I am unable to >> find any information >> on the helper threads in btrfs and would like to known more about how their >> implemented and >> what are the reasons for helper threads in btrfs versus only 1 for >> journaling in ext3/ext3. > > Really? *REALLY*? You can't find anything? What searching did you *DO*? > > [~] cd /usr/src/linux-next/ > [/usr/src/linux-next] ls fs/btrfs > Kconfig btrfs_inode.h delayed-ref.h extent-tree.o hash.c > locking.o props.h root-tree.o transaction.c volumes.h > Makefile built-in.o delayed-ref.o extent_io.c hash.h > lzo.c props.o scrub.c transaction.h volumes.o > acl.c check-integrity.c dev-replace.c extent_io.h hash.o > lzo.o qgroup.c scrub.o transaction.o xattr.c > acl.o check-integrity.h dev-replace.h extent_io.o > inode-item.c math.h qgroup.h send.c tree-defrag.c > xattr.h > async-thread.c compression.c dev-replace.o extent_map.c > inode-item.o modules.order qgroup.o send.h tree-defrag.o > xattr.o > async-thread.h compression.h dir-item.c extent_map.h > inode-map.c ordered-data.c raid56.c send.o tree-log.c > zlib.c > async-thread.o compression.o dir-item.o extent_map.o > inode-map.h ordered-data.h raid56.h struct-funcs.c tree-log.h > zlib.o > backref.c ctree.c disk-io.c file-item.c > inode-map.o ordered-data.o raid56.o struct-funcs.o tree-log.o > backref.h ctree.h disk-io.h file-item.o inode.c > orphan.c rcu-string.h super.c ulist.c > backref.o ctree.o disk-io.o file.c inode.o > orphan.o reada.c super.o ulist.h > btrfs.ko delayed-inode.c export.c file.o ioctl.c > print-tree.c reada.o sysfs.c ulist.o > btrfs.mod.c delayed-inode.h export.h free-space-cache.c ioctl.o > print-tree.h relocation.c sysfs.h uuid-tree.c > btrfs.mod.o delayed-inode.o export.o free-space-cache.h > locking.c print-tree.o relocation.o sysfs.o uuid-tree.o > btrfs.o delayed-ref.c extent-tree.c free-space-cache.o > locking.h props.c root-tree.c tests volumes.c > > Now take a look there in the left-hand column. You *might* find > something useful there. > > As to the rest of your question, the ext filesystems have as a design goal > good performance on 1-2 core machines, while btrfs was designed to take > advantage of high-core-count machines. Hopefully you're a good enough > programmer that I don't have to explain further. > > Thanks for the answers and yes, I was searching in the wiki , not the tree sorry :( fucking brain fart). Thanks for information , in addition , when you mean multiple cores I am curious how many is btrfs scaling to in order to help me understand the locking requirements and more demanding locking I am finding in the btrfs code. Thanks Again for the Help, Nick
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