Re: [PATCH 1/3] mm/compaction: enhance trace output to know more about compaction internals

[Joonsoo Kim]

On Fri, Jan 09, 2015 at 10:57:10AM +0000, Mel Gorman wrote:
> On Thu, Jan 08, 2015 at 09:46:27AM +0100, Vlastimil Babka wrote:
> > On 01/08/2015 09:18 AM, Joonsoo Kim wrote:
> > > On Tue, Jan 06, 2015 at 10:05:39AM +0100, Vlastimil Babka wrote:
> > >> On 12/03/2014 08:52 AM, Joonsoo Kim wrote:
> > >> > It'd be useful to know where the both scanner is start. And, it also be
> > >> > useful to know current range where compaction work. It will help to find
> > >> > odd behaviour or problem on compaction.
> > >> 
> > >> Overall it looks good, just two questions:
> > >> 1) Why change the pfn output to hexadecimal with different printf layout and
> > >> change the variable names and? Is it that better to warrant people having to
> > >> potentially modify their scripts parsing the old output?
> > > 
> > > Deciaml output has really bad readability since we manage all pages by order
> > > of 2 which is well represented by hexadecimal. With hex output, we can
> > > easily notice whether we move out from one pageblock to another one.
> > 
> > OK. I don't have any strong objection, maybe Mel should comment on this as the
> > author of most of the tracepoints? But if it happens, I think converting the old
> > tracepoints to new hexadecimal format should be a separate patch from adding the
> > new ones.
> > 
> 
> To date, I'm not aware of any user-space programs that heavily depend on
> the formatting. The scripts I am aware of are ad-hoc and easily modified
> to adapt to format changes. LTT-NG is the only tool that might be
> depending on trace point formats but I severely doubt it's interested in
> this particular tracepoint.

Okay. Thanks for confirmation!

Thanks.
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