linux-kernel - Re: [GIT PULL 0/6] perf/core improvements and fixes

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:	Fri, 05 Jun 2015 06:48:50 +0900
From:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To:	Alexei Starovoitov <ast@...mgrid.com>,
	Ingo Molnar <mingo@...nel.org>, pi3orama <pi3orama@....com>
CC:	"Wangnan (F)" <wangnan0@...wei.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Brendan Gregg <brendan.d.gregg@...il.com>,
	Daniel Borkmann <daniel@...earbox.net>,
	David Ahern <dsahern@...il.com>, He Kuang <hekuang@...wei.com>,
	Jiri Olsa <jolsa@...hat.com>, Kaixu Xia <xiakaixu@...wei.com>,
	Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>,
	Zefan Li <lizefan@...wei.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Alexei Starovoitov <alexei.starovoitov@...il.com>,
	cti.systems-productivity-manager.ts@...achi.com
Subject: Re: [GIT PULL 0/6] perf/core improvements and fixes

On 2015/06/05 1:22, Alexei Starovoitov wrote:
> On 6/4/15 7:04 AM, Ingo Molnar wrote:
>>>>  # perf record -e bpf_source.c cmdline
>>>>
>>>>  to create a eBPF filter from source,
>>>>
>>>> Use
>>>>
>>>> # perf record -e bpf_object.o cmdline
>>>>
>>>> to create a eBPF filter from object intermedia.
>>>>
>>>> Use
>>>>
>>>> # perf bpf compile bpf_source.c --kbuild=kernel-build-dir -o bpf_object.o
>>>>
>>>> to create the .o
>>>>
>>>> I think this should be enough. Currently only the second case has been implemented.
>> So if users cannot actually generate .o files then it's premature to merge this in
>> such an incomplete form!
>>
>> It should be possible to use a feature that we are merging.
> 
> of course it's usable :) There is some confusion here.
> To compile .c into .o one can easily use
> clang -O2 -emit-llvm -c file.c -o - | llc -march=bpf -o file.o
> any version of clang is ok,
> llc needs to be fresh with bpf backend.
> 
> For a lot of cases kernel headers are not needed, so above
> will work fine.
> For our TC examples we recommend to use 'bcc' alias:
> bcc() {
>    clang -O2 -emit-llvm -c $1 -o - | llc -march=bpf -filetype=obj -o 
> "`basename $1 .c`.o"
> }
> then compiling as easy as 'bcc file.c'
> 
> What Wang mentioned that we're working on is fully integrated 'bcc'.
> It will use clang/llvm as libraries, so no intermediate steps will
> be needed, but some folks will always have concerns about
> ultra-embedded environments where even 20Mb of libllvm.so is too much.
> 
> So I think we need to support both 'perf record -e file.[co]'

I think we'd better make 'perf record -e file.c' default and '-e file.o'
should be an option.

Thank you,

> 
> 


-- 
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu.pt@...achi.com
--
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/