Re: Port the period data column to centos6.7 for perf script

Re: Port the period data column to centos6.7 for perf script

[Andi Kleen]

On Fri, Sep 15, 2017 at 10:24:15AM +0800, 禹舟键 wrote:
>    Hi, all.
>    I want to draw off-cpu flamegraph using perf script on centos6.7(kernel
>    version, 2.6.32-573), and I found perf script lacks the period data column
>    on that version. I  found two related patches, and modifed
>    builin-script.c in reference to those patches.
>    perf script:Add period data column authorJiri Olsa 2014-08-25 16:45:42
>    +0200 commit535aeaae7de821ba5d43ee2a204ee667ca95aae4
>    perf script: Add period as a default output column
>    commite8564b710c6df2c3aeb56c507c22f4bcfa4c0b2d)
> 

I would just compile the newer perf binary for Centos6 and use that. It should
work with older kernels too. That's much easier than backporting, and you get
many more features.

-Andi

Re: Port the period data column to centos6.7 for perf script

[Arnaldo Carvalho de Melo]

Em Thu, Sep 14, 2017 at 09:21:54PM -0700, Andi Kleen escreveu:
> On Fri, Sep 15, 2017 at 10:24:15AM +0800, 禹舟键 wrote:
> >    Hi, all.
> >    I want to draw off-cpu flamegraph using perf script on centos6.7(kernel
> >    version, 2.6.32-573), and I found perf script lacks the period data column
> >    on that version. I  found two related patches, and modifed
> >    builin-script.c in reference to those patches.
> >    perf script:Add period data column authorJiri Olsa 2014-08-25 16:45:42
> >    +0200 commit535aeaae7de821ba5d43ee2a204ee667ca95aae4
> >    perf script: Add period as a default output column
> >    commite8564b710c6df2c3aeb56c507c22f4bcfa4c0b2d)
 
> I would just compile the newer perf binary for Centos6 and use that. It should
> work with older kernels too. That's much easier than backporting, and you get
> many more features.

yeah, look at the Dockerfile I use to build it for that OS:

[acme@jouet 6]$ cat Dockerfile 
# docker.io/acmel/linux-perf-tools-build-centos:6
FROM docker.io/centos:6
MAINTAINER Arnaldo Carvalho de Melo <acme@kernel.org>
RUN yum -y update && \
    yum -y install make gcc flex bison bc elfutils-libelf-devel elfutils-devel \
		   libunwind-devel audit-libs-devel openssl-devel slang-devel \
		   gtk2-devel perl-ExtUtils-Embed python-devel binutils-devel \
		   systemtap-sdt-devel xz-devel numactl-devel && \
    yum -y clean all && \
    rm -rf /usr/share/doc /usr/share/gtk-doc /usr/share/man && \
    mkdir -m 777 -p /tmp/build/perf /tmp/build/objtool && \
    groupadd -r perfbuilder && \
    useradd -m -r -g perfbuilder perfbuilder
USER perfbuilder
ENTRYPOINT make -C /git/linux/tools/perf O=/tmp/build/perf && \
	   rm -rf /tmp/build/perf/{.[^.]*,*} && \
	   make NO_LIBELF=1 -C /git/linux/tools/perf O=/tmp/build/perf && \
	   make -C /git/linux/tools/objtool O=/tmp/build/objtool
[acme@jouet 6]$

Port the period data column to centos6.7 for perf script

[yuzhoujian]

Hi, all.
I want to draw off-cpu flamegraph using perf script on centos6.7
(kernel version, 2.6.32-573), and I found perf script lacks the 
period data column on that version. I found two related patches, 
and modifed builin-script.c in reference to those patches.
perf script:Add period data column authorJiri Olsa 2014-08-25 16:45:42 +0200 
commit535aeaae7de821ba5d43ee2a204ee667ca95aae4
perf script: Add period as a default output column 
commite8564b710c6df2c3aeb56c507c22f4bcfa4c0b2d)


I used the new complied perf to record some hardware event, like cycles, 
and the result displays the period data column. But when I record some 
tracepoint events, like sched:sched_stat_sleep, sched:sched_switch, I 
found the period data column is always 1.  I checked the code(kernel/event/core.c), 
and found that the data->period is assigned nr in the function named perf_swevent_event.  
I tracked this function, and found the function call flow:
perf_trace_buf_submit--->perf_tp_event---->perf_swevent_event.

The function perf_trace_buf_submit is in the ftrace_event.h files, so the period data 
column  for tracepoint events is calulated in the frace subsystem?  What is the real 
meaning of the period field and how to calculate it ? Can you give me some tips for 
poring this field on the old kernel?

Thanks,
Wind Yu.