http://git.kernel.dk/?p=blktrace.git;a=commit;h=8fc451c6b0b9a7db7c376ea6865c35321e561f00 From 8fc451c6b0b9a7db7c376ea6865c35321e561f00 Mon Sep 17 00:00:00 2001 From: Gwendal Grignou Date: Fri, 18 Aug 2017 15:00:22 -0700 Subject: [PATCH] btt: Fix overlapping IO stats. Keep scanning the tree for overlapping IO otherwise Q2G and process traces will be incorrect. Let assume we have 2 IOs: A A+a |---------------------------------------| B B+b |-----------------| In the red/black tree we have: o -> [A,A+a] / \ left right / \ [...]o o -> [B, B+b] In the current code, if we would not be able to find [B+b] in the tree: B is greater than A, so we won't go left B+b is smaller than A+a, so we are not going right either. When we have a [X, X+x] IO to look for: We need to check for right when either: X+x >= A+a (for merged IO) and X > A (for overlapping IO) TEST=Check with a trace with overlapping IO: Q2C and Q2G are expected. Signed-off-by: Gwendal Grignou Signed-off-by: Jens Axboe --- btt/dip_rb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/btt/dip_rb.c b/btt/dip_rb.c index 2aa7ffcc763b..6efef6c03b8f 100644 --- a/btt/dip_rb.c +++ b/btt/dip_rb.c @@ -57,7 +57,7 @@ struct io *rb_find_sec(struct rb_root *root, __u64 sec) __iop = rb_entry(n, struct io, rb_node); if (sec < BIT_START(__iop)) n = n->rb_left; - else if (sec >= BIT_END(__iop)) + else if (sec > BIT_START(__iop)) n = n->rb_right; else return __iop; @@ -82,7 +82,7 @@ void rb_foreach(struct rb_node *n, struct io *iop, } if (iop_s < this_s) rb_foreach(n->rb_left, iop, fnc, head); - if (this_e < iop_e) + if ((this_e < iop_e) || (this_s < iop_s)) rb_foreach(n->rb_right, iop, fnc, head); } } -- 2.15.1