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Message-ID: <20140523173026.GQ50500@redhat.com>
Date: Fri, 23 May 2014 13:30:26 -0400
From: Don Zickus <dzickus@...hat.com>
To: Jiri Olsa <jolsa@...hat.com>
Cc: acme@...stprotocols.net, peterz@...radead.org,
LKML <linux-kernel@...r.kernel.org>, namhyung@...il.com,
eranian@...gle.com, Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH 6/7] perf: Add support to dynamically get cacheline size
On Fri, May 23, 2014 at 07:09:01PM +0200, Jiri Olsa wrote:
> On Mon, May 19, 2014 at 03:13:52PM -0400, Don Zickus wrote:
>
> SNIP
>
> > diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
> > index 61a6548..b3e7b22 100644
> > --- a/tools/perf/util/cpumap.h
> > +++ b/tools/perf/util/cpumap.h
> > @@ -81,4 +81,16 @@ static inline int cpu__get_node(int cpu)
> > return cpunode_map[cpu];
> > }
> >
> > +int cacheline_size;
>
> hum, so cacheline_size does not need to be global, if you use
> cpu__cacheline_size in your next patch, right?
I made cpu__cacheline_size an inline so I think it does. If I stick that
function in cpumap.c then yeah I would agree it would not need to be
global.
Being that is was going to be called repeatedly while processing each
event I opted to make it an inline. I guess I could change that if it
matters.
>
> > +
> > +int cpu__setup_cacheline_size(void);
> > +
> > +static inline int cpu__cacheline_size(void)
> > +{
> > + if (unlikely(!cacheline_size))
> > + pr_debug("cacheline size not initialized\n");
> > +
> > + return cacheline_size;
> > +}
> > +
> > #endif /* __PERF_CPUMAP_H */
> > diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> > index 635cd8f..50adbfb 100644
> > --- a/tools/perf/util/sort.c
> > +++ b/tools/perf/util/sort.c
> > @@ -2,6 +2,7 @@
> > #include "hist.h"
> > #include "comm.h"
> > #include "symbol.h"
> > +#include "cpumap.h"
> >
> > regex_t parent_regex;
> > const char default_parent_pattern[] = "^sys_|^do_page_fault";
> > @@ -1117,6 +1118,8 @@ int setup_sorting(void)
> > return -ENOMEM;
> > }
> >
> > + cpu__setup_cacheline_size();
> > +
>
> I dont think this is the best place to call the setup,
> on the other hand I can't think of any suitable ;-)
>
> how about lazy initialization from cpu__cacheline_size?
>
> We also have page_size variable which gets initialized
> in main and is globaly accesable. I wonder we should
> add the cacheline_size variable in the same way.
That seems to make sense. I can stick the variable in util.c|h then?
Cheers,
Don
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