linux-kernel - Re: native_save_fl taking good amount of time in profile

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] [day] [month] [year] [list]

Message-ID: <4FC4C943.2030007@gmail.com>
Date:	Tue, 29 May 2012 21:04:03 +0800
From:	Liu Zhiyou <liuzhiyou.cs@...il.com>
To:	Xin Tong <xerox.time.tech@...il.com>
CC:	Andi Kleen <andi@...stfloor.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: native_save_fl taking good amount of time in profile

于 2012年05月26日 07:10, Xin Tong 写道:
> i do not know its callers from the profile. one thing i am suspicious
> of is that my kernel debug-info is wrong. by the way, what does the
> function do ?
>
> Thanks
>
> Xin
>
>
> On Fri, May 25, 2012 at 6:27 PM, Andi Kleen<andi@...stfloor.org>  wrote:
>> Xin Tong<xerox.time.tech@...il.com>  writes:
>>
>>> I have collected a profile on the whole system. But the only thing
>>> that is really running is a mysql database server. I have noticed that
>>> there is a function in kernel that took 5% of the overall running
>>> time. what does native_save_fl do ? does it make sense that
>>> native_save_fl takes the most amount of time among all kernel
>>> functions ?
>> What are the callers (-g)? It does not make sense normally.
>> -Andi
Xin Tong,

Use perf record -g, then it will give you a call-graph.
$ man perf-record
-g, --call-graph
Do call-graph (stack chain/backtrace) recording.
$ man pref-report
-g [type,min[,limit],order], --call-graph
Display call chains using type, min percent threshold, optional print 
limit and order. type can be either:

· flat: single column, linear exposure of call chains.

· graph: use a graph tree, displaying absolute overhead rates.

· fractal: like graph, but displays relative rates. Each branch of the 
tree is considered as a new profiled object.

order can be either:
- callee: callee based call graph.
- caller: inverted caller based call graph.

Default: fractal,0.5,callee.

Regards,
LIU Zhiyou
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/