On 2017/10/11 3:00, Arnaldo Carvalho de Melo wrote:
Em Tue, Oct 10, 2017 at 03:36:28PM -0300, Arnaldo Carvalho de Melo escreveu:
Em Tue, Oct 10, 2017 at 03:34:55PM -0300, Arnaldo Carvalho de Melo escreveu:
Em Tue, Oct 10, 2017 at 06:28:18PM +0000, Liang, Kan escreveu:
Em Tue, Oct 10, 2017 at 10:20:16AM -0700, kan.li...@intel.com escreveu:
From: Kan Liang <kan.li...@intel.com>
The perf_evlist__mmap_read only support forward mode. It needs a
common function to support both forward and backward mode.
The perf_evlist__mmap_read_backward is buggy.
So, what is the bug? You state that it is buggy, but don't spell out the bug,
please do so.
union perf_event *perf_evlist__mmap_read_backward(struct perf_evlist *evlist,
int idx)
{
struct perf_mmap *md = &evlist->mmap[idx]; <--- it should be
backward_mmap
If it fixes an existing bug, then it should go separate from this patchkit,
right?
There is no one use perf_evlist__mmap_read_backward. So it doesn't trigger any
issue.
There is no one at the end of your patchkit? Or no user _right now_? If
there is a user now, lemme see... yeah, no user right now, so _that_ is
yet another bug, i.e. it should be used, no? If this is just a left
over, then we should just throw it away, now, its a cleanup.
Wang, can you take a look at these two issues?
So it looks leftover that should've been removed by the following cset, right
Wang?
- Arnaldo
commit a0c6f451f90204847ce5f91c3268d83a76bde1b6
Author: Wang Nan <wangn...@huawei.com>
Date: Thu Jul 14 08:34:41 2016 +0000
perf evlist: Drop evlist->backward
Now there's no real user of evlist->backward. Drop it. We are going to
use evlist->backward_mmap as a container for backward ring buffer.
Yes, it should be removed, but then there will be no corresponding
function to perf_evlist__mmap_read(), which read an record from forward
ring buffer.
I think Kan wants to become the first user of this function because
he is trying to make 'perf top' utilizing backward ring buffer. It needs
perf_evlist__mmap_read_backward(), and he triggers the bug use his
unpublished patch set.
I think we can remove it now, let Kan fix and add it back in his 'perf top'
patch set.
Thank you.
