From: David Ahern <dsahern@gmail.com>
To: Robert Richter <robert.richter@amd.com>
Cc: acme@ghostprotocols.net, linux-kernel@vger.kernel.org,
peterz@infradead.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 3/3] perf tool: give user better message if precise is not supported
Date: Tue, 11 Sep 2012 08:32:55 -0600 [thread overview]
Message-ID: <504F4B97.3040701@gmail.com> (raw)
In-Reply-To: <20120911140148.GV8285@erda.amd.com>
On 9/11/12 8:01 AM, Robert Richter wrote:
>
> Ok, wrong question. Better would have been: Did you run it on a
> non-pebs Intel machine of an non-ibs AMD machine?
Intel: yes. VM for example. All the servers I have now are Nehalem or
better - ie., with a PEBS.
AMD: no. I do not have any AMD-based servers.
>
>> I do not post patches without testing them. This particular patch was
>> verified in a Virtual Machine (no PEBS) and using :pG modifier.
>>
>> 'egrep -r ENOTSUP tools/perf' shows hits in 3 other files, so I am not
>> the only one using the shortcut. I'll change it in the follow up with
>> better commit messages to make it consistent with patch 2.
>
> For VM this might be valid. Don't know where ENOTSUP comes from. It is
> neither in kernel/events/ nor arch/x86/kernel/cpu/perf.
My guess would be /usr/include/bits/errno.h:
/* Linux has no ENOTSUP error code. */
# define ENOTSUP EOPNOTSUPP
>
> If you run this bare-metal on older machines which do not support pebs
> or ibs, the syscall returns EOPNOTSUPP. You can trigger the same
> behaviour on newer systems with:
>
> # perf record -e cycles:ppp -c 2097120 -R -a sleep 1
>
> Error: sys_perf_event_open() syscall returned with 95 (Operation not supported). /bin/dmesg may provide additional information.
> ...
>
> It should work in this case too.
The commit message was a copy and paste from the failure of both :p in a
VM (PEBS is not supported in a VM). I also ran the bare metal case with
:pG which per the second patch in this series generates the not
supported message.
David
next prev parent reply other threads:[~2012-09-11 14:33 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-10 16:40 [PATCH 0/3] perf: precise mode and exclude_guest David Ahern
2012-09-10 16:40 ` [PATCH 1/3] perf tool: precise mode requires exclude_guest David Ahern
2012-09-10 17:23 ` Peter Zijlstra
2012-09-10 16:40 ` [PATCH 2/3] perf: require exclude_guest to use PEBS - kernel side enforcement David Ahern
2012-09-10 17:24 ` Peter Zijlstra
2012-09-10 16:40 ` [PATCH 3/3] perf tool: give user better message if precise is not supported David Ahern
2012-09-11 9:20 ` Robert Richter
2012-09-11 13:22 ` David Ahern
2012-09-11 14:01 ` Robert Richter
2012-09-11 14:32 ` David Ahern [this message]
2012-09-11 15:11 ` Robert Richter
2012-09-12 14:59 ` David Ahern
2012-09-10 16:57 ` [PATCH 0/3] perf: precise mode and exclude_guest Peter Zijlstra
2012-09-10 17:01 ` David Ahern
2012-09-10 17:13 ` Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=504F4B97.3040701@gmail.com \
--to=dsahern@gmail.com \
--cc=acme@ghostprotocols.net \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=robert.richter@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).