Re: perf version issues

[John Garry <john.garry@huawei.com>]

On 22/03/2022 20:11, Arnaldo Carvalho de Melo wrote:

Hi Arnaldo,

> $ git cherry-pick cb66befccba18fac
>    [perf/core 8ff6a6c06a90a362] perf tools: Fix version kernel tag
>     Author: John Garry<john.garry@huawei.com>
>     Date: Mon Feb 21 21:16:49 2022 +0800
>     1 file changed, 4 insertions(+), 9 deletions(-)
>    $ make -C tools/perf O=/tmp/build/perf install-bin
>    $ perf -v
>    perf version 5.17.rc8.g4e666cdb06ee
> 
> Now it doesn´t notice it and there is no automatic rebuild triggered, we
> stay with the cset from before the cherry-pick:-\
> 
> $ git log --oneline -2
> 8ff6a6c06a90a362 (HEAD -> perf/core) perf tools: Fix version kernel tag
> 4e666cdb06eede20 perf tools: Fix dependency for version file creation
> $
> 
> Anyway, your patch works for some cases, so its an improvement and I'll
> apply it, we can continue from there.

After some experimentation, I find that only .git/HEAD changes for a 
cherry-pick depending on whether we're on a branch or not. As such, as 
you have seen, we may not rebuild after a cherry-pick, which is no good.

As far as I can see, only .git/index changes in all circumstances, but 
we don't have a dependency on that.

TBH, using .git files as Makefile dependencies doesn't seem to work well.

Maybe we should output "git log" and check versus what we have in 
PERF-VERSION-FILE and re-build depending on that.

Let me check this further now.

Thanks,
john