Re: [PATCH 6/6] perf: Add dcacheline sort

Jiri Olsa
2014-05-19T13:35:06Z

On Fri, May 16, 2014 at 10:30:02AM -0400, Don Zickus wrote:
> On Fri, May 16, 2014 at 04:05:51PM +0200, Jiri Olsa wrote:
> > On Fri, May 16, 2014 at 09:30:58AM -0400, Don Zickus wrote:
> > > On Fri, May 16, 2014 at 01:47:57PM +0200, Jiri Olsa wrote:
> > > > On Tue, May 13, 2014 at 12:48:17PM -0400, Don Zickus wrote:
> > > > > In perf's 'mem-mode', one can get access to a whole bunch of details specific to a
> > > > > particular sample instruction. A bunch of those details relate to the data
> > > > > address.
> > > > >
> > > > > One interesting thing you can do with data addresses is to convert them into a unique
> > > > > cacheline they belong too. Organizing these data cachelines into similar groups and sorting
> > > > > them can reveal cache contention.
> > > > >
> > > > > This patch creates an alogorithm based on various sample details that can help group
> > > > > entries together into data cachelines and allows 'perf report' to sort on it.
> > > > >
> > > > > The algorithm relies on having proper mmap2 support in the kernel to help determine
> > > > > if the memory map the data address belongs to is private to a pid or globally shared.
> > > > >
> > > > > The alogortithm is as follows:
> > > > >
> > > > > o group cpumodes together
> > > > > o group entries with discovered maps together
> > > > > o sort on major, minor, inode and inode generation numbers
> > > > > o if userspace anon, then sort on pid
> > > > > o sort on cachelines based on data addresses
> > > >
> > > > needs some collumn width refresh or something..? ;-)
> > >
> > > Not sure what you mean here.
> > >
> > > >
> > > > # Overhead Data Cacheline
> > > > # ........ .......................
> >
> > header not being wide enough to cover the longest data
>
> Ah. Ok. So I am not sure the right way to fix that. As the current
> header seems to be hardcoded with a bunch of spaces. Is there a trick to
> dynamically space it correctly based on the data provided?

it should be enough to update function:
void hists__calc_col_len(struct hists *hists, struct hist_entry *h)

with HISTC_MEM_DCACHELINE column update code, same as the rest

jirka