linux-kernel - perf top broken on ppc64

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <594EC076-62C6-473D-9AF2-47AEE4B57ED3@suse.de>
Date:	Wed, 21 Apr 2010 01:21:36 +0200
From:	Alexander Graf <agraf@...e.de>
To:	Paul Mackerras <paulus@...ba.org>
Cc:	LKML Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	ppc-dev <linuxppc-dev@...ts.ozlabs.org>
Subject: perf top broken on ppc64

Hi,

While trying to find out performance bottlenecks in KVM for PowerPC I figured I'd try and use "perf top" to see what's going on in the system. This works great on my G4, but doesn't on the Powerstation (970MP).

The only weird thing I can imagine about this setup is that I'm running 32 bit userland on a 64 bit kernel. So I went ahead and compiled perf for ppc64 - without any change:

# file `which perf`
/root/bin/perf: ELF 64-bit MSB executable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), for GNU/Linux 2.6.4, dynamically linked (uses shared libs), not stripped

Whenever I call 'perf top' I get the following output:

-------------------------------------------------------------------------------------------------------
   PerfTop:   57159 irqs/sec  kernel:100.0% [1000Hz cycles],  (all, 4 CPUs)
-------------------------------------------------------------------------------------------------------

             samples  pcnt  DSO
             _______ _____  

Where there would usually be functions being listed I don't get anything.
The interesting part is that 'perf record -g' and 'perf report -g' work just fine. I get reasonable output. I also had 'perf top' with the exact same binaries working by accident too once. But then I rebooted and not it's all moot again.

So the question is: why doesn't the top function work for me?

Thanks,

Alex

--
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/