Re: [PATCH linux-2.6-block.git] Fix blktrace trace ordering for plug branch

[Jens Axboe <jens.axboe@oracle.com>]

On Fri, Apr 27 2007, Alan D. Brunelle wrote:
> The attached patch will correct the ordering of trace output between 
> request queue insertions (I) and unplug calls (U). Right now the insert 
> precedes the unplug, which just isn't right:
> 
> 65,128  0        1    67.699868965  7882  Q   R 0 + 1 [aiod]
> 65,128  0        2    67.699876462  7882  G   R 0 + 1 [aiod]
> 65,128  0        3    67.699878286  7882  P   W [aiod]
> 65,128  0        4    67.699880491  7882  I   R 0 + 1 [aiod]
> 65,128  0        5    67.699887589  7882  U   R [aiod] 1
> 65,128  0        6    67.699898317    54  D   R 0 + 1 [kblockd/0]
> 65,128  2      153    67.700126590     0  C   R 0 + 1 [0]
> 
> With the patch provided the unplug comes first:
> 
> 65,128  3        1     0.000000000  7045  Q   R 0 + 1 [aiod]
> 65,128  3        2     0.000002295  7045  G   R 0 + 1 [aiod]
> 65,128  3        3     0.000002617  7045  P   W [aiod]
> 65,128  3        4     0.000003685  7045  U   R [aiod] 1
> 65,128  3        5     0.000004107  7045  I   R 0 + 1 [aiod]
> 65,128  3        6     0.000009491    57  D   R 0 + 1 [kblockd/3]
> 65,128  2        1     0.000232447     0  C   R 0 + 1 [0]
> 
> Jens: If you agree, the patch can be applied to your plug branch for 
> git://git.kernel.dk/data/git/linux-2.6-block.git

Thanks, with that applied the unplug ordering should be the same after
the plugging changes. Applied.

-- 
Jens Axboe