| http://git.kernel.dk/?p=blktrace.git;a=commit;h=8fc451c6b0b9a7db7c376ea6865c35321e561f00 |
| |
| From 8fc451c6b0b9a7db7c376ea6865c35321e561f00 Mon Sep 17 00:00:00 2001 |
| From: Gwendal Grignou <gwendal@chromium.org> |
| 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 <gwendal@chromium.org> |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| --- |
| 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 |
| |
