[RFC] perf top and deleted binaries

[RFC] perf top and deleted binaries

[Arun Sharma]

For long running binaries which may have been replaced or deleted, today 
perf top spits out a warning and doesn't show anything. For eg:

test.c:

main()
{
	while(1);
}

gcc -O2 test.c -o test
./test &
gcc -O2 test.c -o test	# overwrite the binary
perf top -p <pid>

shows nothing. It could instead show:

100% <unresolved>	test

like perf record/report would show for the same test case. Comments?

 -Arun

Re: [RFC] perf top and deleted binaries

[Arnaldo Carvalho de Melo]

Em Mon, May 09, 2011 at 11:28:23AM -0700, Arun Sharma escreveu:
> 
> For long running binaries which may have been replaced or deleted, today 
> perf top spits out a warning and doesn't show anything. For eg:
> 
> test.c:
> 
> main()
> {
> 	while(1);
> }
> 
> gcc -O2 test.c -o test
> ./test &
> gcc -O2 test.c -o test	# overwrite the binary
> perf top -p <pid>
> 
> shows nothing. It could instead show:
> 
> 100% <unresolved>	test
> 
> like perf record/report would show for the same test case. Comments?

Agreed :-)

When/if we get build-id as first class citizen, stashing it in some
kernel data structure at DSO load time, we'll be able to use it for
content based DSO lookup in the cache.

- Arnaldo