[Darshan-users] Consecutive vs. Sequential?

[Phil Carns]

Hi Jeff,

That's not a silly question at all :)

Darshan labels an access as sequential if it occurs at an offset > the 
last byte accessed in the file (basically anything that doesn't seek 
backwards or overlap the preceding operation).

Darshan labels an access as consecutive if it occurs at an offset 
exactly the last byte accessed + 1 (i.e. sequential, but with no gaps at 
all between operations).

Both metrics are from the perspective of a single process.  So it is 
conceivable that a collection of ranks could produce a workload that 
looks consecutive at the file system level, but is interleaved among 
ranks such that it only counts as sequential at the process level.

thanks,

-Phil

On 8/9/21 10:38 AM, Jeffrey Layton wrote:
> Good morning,
>
> I have a question about the job summary output. There is a bar chart 
> with bars labeled as "sequential" and "consecutive". How are these 
> defined?
>
> Thanks!
>
> Jeff
>
> P.S. Apologies for the silly Monday morning question.
>
>
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