From 423e95ccbe2e2612ed9fe41667acfc338f3af07b Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Thu, 5 Sep 2013 10:07:15 +0900 Subject: f2fs: merge more bios of node block writes Previously, we experience bio traces as follows when running simple sequential write test. f2fs_do_submit_bio: type = NODE, io = no sync, sector = 500104928, size = 4K f2fs_do_submit_bio: type = NODE, io = no sync, sector = 499922208, size = 368K f2fs_do_submit_bio: type = NODE, io = no sync, sector = 499914752, size = 140K -> total 512K The first one is to write an indirect node block, and the others are to write direct node blocks. The reason why there are two separate bios for direct node blocks is: 0. initial state ------------------ ------------------ | | |xxxxxxxx | ------------------ ------------------ 1. write 368K ------------------ ------------------ | | |xxxxxxxxWWWWWWWW| ------------------ ------------------ 2. write 140K ------------------ ------------------ |WWWWWWW | |xxxxxxxxWWWWWWWW| ------------------ ------------------ This is because f2fs_write_node_pages tries to write just 512K totally, so that we can lose the chance to merge more bios nicely. After this patch is applied, we can get the following bio traces. f2fs_do_submit_bio: type = NODE, io = no sync, sector = 500103168, size = 8K f2fs_do_submit_bio: type = NODE, io = no sync, sector = 500111368, size = 4K f2fs_do_submit_bio: type = NODE, io = no sync, sector = 500107272, size = 512K f2fs_do_submit_bio: type = NODE, io = no sync, sector = 500108296, size = 512K f2fs_do_submit_bio: type = NODE, io = no sync, sector = 500109320, size = 500K And finally, we can improve the sequential write performance, from 458.775 MB/s to 479.945 MB/s on SSD. Signed-off-by: Jaegeuk Kim --- fs/f2fs/node.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'fs/f2fs') diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index c3c03c975bd..51ef2789443 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1191,9 +1191,9 @@ static int f2fs_write_node_page(struct page *page, /* * It is very important to gather dirty pages and write at once, so that we can * submit a big bio without interfering other data writes. - * Be default, 512 pages (2MB), a segment size, is quite reasonable. + * Be default, 512 pages (2MB) * 3 node types, is more reasonable. */ -#define COLLECT_DIRTY_NODES 512 +#define COLLECT_DIRTY_NODES 1536 static int f2fs_write_node_pages(struct address_space *mapping, struct writeback_control *wbc) { @@ -1211,9 +1211,10 @@ static int f2fs_write_node_pages(struct address_space *mapping, return 0; /* if mounting is failed, skip writing node pages */ - wbc->nr_to_write = max_hw_blocks(sbi); + wbc->nr_to_write = 3 * max_hw_blocks(sbi); sync_node_pages(sbi, 0, wbc); - wbc->nr_to_write = nr_to_write - (max_hw_blocks(sbi) - wbc->nr_to_write); + wbc->nr_to_write = nr_to_write - (3 * max_hw_blocks(sbi) - + wbc->nr_to_write); return 0; } -- cgit v1.2.3-18-g5258