linux-kernel - Re: [PATCH v7] perf annotate: Fix sample events lost in stdio mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YHbexV5LtJWMqJra@kernel.org>
Date:   Wed, 14 Apr 2021 09:23:33 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Yang Jihong <yangjihong1@...wei.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Yao Jin <yao.jin@...ux.intel.com>, gustavoars@...nel.org,
        mliska@...e.cz, linux-kernel <linux-kernel@...r.kernel.org>,
        zhangjinhao2@...wei.com, Namhyung Kim <namhyung@...nel.org>
Subject: Re: [PATCH v7] perf annotate: Fix sample events lost in stdio mode

Em Mon, Apr 12, 2021 at 03:22:29PM +0800, Yang Jihong escreveu:
> On 2021/3/31 10:18, Yang Jihong wrote:
> > On 2021/3/30 15:26, Namhyung Kim wrote:
> > > On Sat, Mar 27, 2021 at 11:16 AM Yang Jihong <yangjihong1@...wei.com> wrote:
> > > > On 2021/3/26 20:06, Arnaldo Carvalho de Melo wrote:
> > > > > So it seems to be working, what am I missing? Is this strictly non
> > > > > group related?

> > > > Yes, it is non group related.
> > > > This problem occurs only when different events need to be recorded at
> > > > the same time, i.e.:
> > > > perf record -e branch-misses -e branch-instructions -a sleep 1

> > > > The output results of perf script and perf annotate do not match.
> > > > Some events are not output in perf annotate.

> > > Yeah I think it's related to sort keys.  The code works with a single
> > > hist_entry for each event and symbol.  But the default sort key
> > > creates multiple entries for different threads and it causes the
> > > confusion.

> > Yes, After revome zfree from hists__find_annotations, the output of perf
> > annotate is repeated, which is related to sort keys.

> > The original problem is that notes->src may correspond to multiple
> > sample events. Therefore, we cannot simply zfree notes->src to avoid
> > repeated output.

> > Arnaldo, is there any problem with this patch? :)

> PING :)
> Is there any problem with this patch that needs to be modified?

I continue having a feeling this is kinda a bandaid, i.e. avoid the
problem, and since we have a way to work this when using a group, I fail
to see why it couldn't work when not grouping events.

But since I have no time to dive into this and Namhyung is ok with it,
I'll merge it now.

- Arnaldo