From: Peter Zijlstra <peterz@infradead.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
Wang Nan <wangnan0@huawei.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Stephane Eranian <eranian@google.com>,
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 1/6] powerpc/perf: Define big-endian version of perf_mem_data_src
Date: Mon, 6 Mar 2017 16:28:56 +0100 [thread overview]
Message-ID: <20170306152856.GO6500@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DCFE78C84@AcuExch.aculab.com>
On Mon, Mar 06, 2017 at 02:59:07PM +0000, David Laight wrote:
> From: Peter Zijlstra
> > Sent: 06 March 2017 11:22
> > To: Madhavan Srinivasan
> > Cc: Wang Nan; Alexander Shishkin; linux-kernel@vger.kernel.org; Arnaldo Carvalho de Melo; Alexei
> > Starovoitov; Ingo Molnar; Stephane Eranian; Sukadev Bhattiprolu; linuxppc-dev@lists.ozlabs.org
> > Subject: Re: [PATCH v2 1/6] powerpc/perf: Define big-endian version of perf_mem_data_src
> >
> > On Mon, Mar 06, 2017 at 04:13:08PM +0530, Madhavan Srinivasan wrote:
> > > From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> > >
> > > perf_mem_data_src is an union that is initialized via the ->val field
> > > and accessed via the bitmap fields. For this to work on big endian
> > > platforms, we also need a big-endian represenation of perf_mem_data_src.
> >
> > Doesn't this break interpreting the data on a different endian machine?
>
> Best to avoid bitfields if you ever care about the bit order.
Too late for that. But perf tool has quite a bit of code to muck fields
between different endians. With the full intent that generation on one
machine is readable by another.
next prev parent reply other threads:[~2017-03-06 15:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-06 10:43 [PATCH v2 0/6] powerpc/perf: Export memory hierarchy level Madhavan Srinivasan
2017-03-06 10:43 ` [PATCH v2 1/6] powerpc/perf: Define big-endian version of perf_mem_data_src Madhavan Srinivasan
2017-03-06 11:22 ` Peter Zijlstra
2017-03-06 14:59 ` David Laight
2017-03-06 15:28 ` Peter Zijlstra [this message]
2017-03-07 9:58 ` Madhavan Srinivasan
2017-03-07 10:23 ` Peter Zijlstra
2017-03-13 11:15 ` Madhavan Srinivasan
2017-03-13 12:50 ` Peter Zijlstra
2017-03-14 9:01 ` Madhavan Srinivasan
2017-03-14 12:56 ` Peter Zijlstra
2017-03-15 6:20 ` Michael Ellerman
2017-03-15 12:23 ` Peter Zijlstra
2017-03-16 5:53 ` Madhavan Srinivasan
2017-03-16 5:47 ` Madhavan Srinivasan
2017-03-06 10:43 ` [PATCH v2 2/6] powerpc/perf: Export memory hierarchy info to user space Madhavan Srinivasan
2017-03-13 19:21 ` Sukadev Bhattiprolu
2017-03-06 10:43 ` [PATCH v2 3/6] powerpc/perf: Support to export MMCRA[TEC*] field to userspace Madhavan Srinivasan
2017-03-06 10:43 ` [PATCH v2 4/6] powerpc/perf: Support to export SIERs bit in Power8 Madhavan Srinivasan
2017-03-06 10:43 ` [PATCH v2 5/6] powerpc/perf: Support to export SIERs bit in Power9 Madhavan Srinivasan
2017-03-06 10:43 ` [PATCH v2 6/6] powerpc/perf: Add Power8 mem_access event to sysfs Madhavan Srinivasan
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