Re: [PATCH 1/4] perf tools: pass PYTHON config to feature detection

[David Carrillo-Cisneros]

On Tue, Feb 7, 2017 at 11:47 AM, Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
> Em Wed, Feb 01, 2017 at 10:38:01PM -0800, David Carrillo-Cisneros escreveu:
>> Python's CC and link Makefile variables were not passed to feature
>> detection, causing feature detection to use system's Python rather than
>> PYTHON_CONFIG's one. This created a mismatch between the detected Python
>> support and the one actually used by perf when PYTHON_CONFIG is specified.
>>
>> Fix it by moving Python's variable initialization to before feature
>> detection and pass FLAGS_PYTHON_EMBED to Python's feature detection's
>> build target.
>
> So, all builds on Ubuntu with the devel files for perf end up with:
>
> ubuntu:12.04.5, 14.04.4, 16.04, 16.10 (cross builds, native ones)
>
>   GEN      /tmp/build/perf/libtraceevent-dynamic-list
> /bin/sh: 1: [: U: unexpected operator
> Either missing one of [ /tmp/build/perf/plugin_jbd2.so /tmp/build/perf/plugin_hrtimer.so /tmp/build/perf/plugin_kmem.so /tmp/build/perf/plugin_kvm.so /tmp/build/perf/plugin_mac80211.so /tmp/build/perf/plugin_sched_switch.so /tmp/build/perf/plugin_function.so /tmp/build/perf/plugin_xen.so /tmp/build/perf/plugin_scsi.so /tmp/build/perf/plugin_cfg80211.so] or bad version of nm
>
> Details:
>
> perfbuilder@341e71da5019:/git/linux$ cat /etc/os-release
> NAME="Ubuntu"
> VERSION="16.10 (Yakkety Yak)"
> ID=ubuntu
> ID_LIKE=debian
> PRETTY_NAME="Ubuntu 16.10"
> VERSION_ID="16.10"
> HOME_URL="http://www.ubuntu.com/";
> SUPPORT_URL="http://help.ubuntu.com/";
> BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/";
> PRIVACY_POLICY_URL="http://www.ubuntu.com/legal/terms-and-policies/privacy-policy";
> VERSION_CODENAME=yakkety
> UBUNTU_CODENAME=yakkety
> perfbuilder@341e71da5019:/git/linux$ ls -la /tmp/build/perf/plugin_jbd2.so /tmp/build/perf/plugin_hrtimer.so /tmp/build/perf/plugin_kmem.so /tmp/build/perf/plugin_kvm.so /tmp/build/perf/plugin_mac80211.so /tmp/build/perf/plugin_sched_switch.so /tmp/build/perf/plugin_function.so /tmp/build/perf/plugin_xen.so /tmp/build/perf/plugin_scsi.so /tmp/build/perf/plugin_cfg80211.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 13576 Feb  7 19:38 /tmp/build/perf/plugin_cfg80211.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 20256 Feb  7 19:38 /tmp/build/perf/plugin_function.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 13680 Feb  7 19:38 /tmp/build/perf/plugin_hrtimer.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 13760 Feb  7 19:38 /tmp/build/perf/plugin_jbd2.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 13976 Feb  7 19:38 /tmp/build/perf/plugin_kmem.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 28680 Feb  7 19:38 /tmp/build/perf/plugin_kvm.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 14248 Feb  7 19:38 /tmp/build/perf/plugin_mac80211.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 18800 Feb  7 19:38 /tmp/build/perf/plugin_sched_switch.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 20136 Feb  7 19:38 /tmp/build/perf/plugin_scsi.so
> -rwxr-xr-x. 1 perfbuilder perfbuilder 14504 Feb  7 19:38 /tmp/build/perf/plugin_xen.so
> perfbuilder@341e71da5019:/git/linux$
>
> perfbuilder@341e71da5019:/git/linux$ file=/tmp/build/perf/plugin_jbd2.so ; nm -u -D $file | awk 'NF>1 {print $$file}' | sort -u
>                  U pevent_register_print_function
>                  U pevent_unregister_print_function
>                  U trace_seq_printf
> perfbuilder@341e71da5019:/git/linux$
>
>

Thanks for testing it.

I found that some *.so files in Ubuntu have the "w" value in nm's
otput symbol type. From man nm:

           "W"
           "w" The symbol is a weak symbol that has not been
specifically tagged as a weak object symbol.  When a
               weak defined symbol is linked with a normal defined
symbol, the normal defined symbol is used with
               no error.  When a weak undefined symbol is linked and
the symbol is not defined, the value of the
               symbol is determined in a system-specific manner
without error.  On some systems, uppercase
               indicates that a default value has been specified.


I'll send an updated patch that expects and includes undefined weak symbols.

Thanks,
David