linux-kernel - Re: [PATCH v3 6/8] perf session: Move event read code to separate function

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]

Date:   Mon, 11 Oct 2021 12:08:57 +0300
From:   "Bayduraev, Alexey V" <alexey.v.bayduraev@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Antonov <alexander.antonov@...ux.intel.com>,
        Alexei Budankov <abudankov@...wei.com>,
        Riccardo Mancini <rickyman7@...il.com>
Subject: Re: [PATCH v3 6/8] perf session: Move event read code to separate
 function


On 08.10.2021 17:38, Jiri Olsa wrote:
> On Fri, Oct 08, 2021 at 11:42:18AM +0300, Bayduraev, Alexey V wrote:
>>
>>
>> On 08.10.2021 10:33, Jiri Olsa wrote:
>>> On Thu, Oct 07, 2021 at 01:25:41PM +0300, Alexey Bayduraev wrote:
>>>
>>> SNIP
>>>
>>>>  static int
>>>> -reader__process_events(struct reader *rd, struct perf_session *session,
>>>> -		       struct ui_progress *prog)
>>>> +reader__read_event(struct reader *rd, struct perf_session *session,
>>>> +		   struct ui_progress *prog)

SNIP

>>>
>>> active_decomp should be set/unset within reader__process_events,
>>> not just for single event read, right?
>>
>> No, it should be set before perf_session__process_event/process_decomp_events
>> and unset after these calls. So active_decomp setting/unsetting is moved in
>> this patch to the reader__read_event function. This is necessary for multiple
>> trace reader because it could call reader__read_event in round-robin manner.
> 
> hum, is that code already in? I can't see this happening in current code

Probably I don't understand the question. In [PATCH v3 2/8] I introduced 
active_decomp pointer in perf_session. It is initialized by a pointer to the 
decompressor object in perf_session. In reader__process_events it is set to 
the reader decompressor object. And it is reset to the session decompressor 
object at exit. In this case we do not need to reset it after each 
perf_session__process_event because this code reads events in loop with 
constant reader object. Maybe setting of active_decomp should be at the 
entrance to the reader__process_events, not before reader__process_events, 
in [PATCH v3 2/8]. All this code is new.

In this patch I separates single event reading and moves setting/resetting
of active_decomp before/after perf_session__process_event because this is 
necessary for multiple trace reader. 

Regards,
Alexey

> 
> jirka
> 
>>
>> Regards,
>> Alexey
>>
>>>
>>> jirka
>>>
>>>>  	return err;
>>>>  }
>>>>  
>>>> -- 
>>>> 2.19.0
>>>>
>>>
>>
>