From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752994AbcAGId2 (ORCPT ); Thu, 7 Jan 2016 03:33:28 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47190 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752952AbcAGIdW (ORCPT ); Thu, 7 Jan 2016 03:33:22 -0500 Date: Thu, 7 Jan 2016 09:33:19 +0100 From: Jiri Olsa To: kan.liang@intel.com Cc: peterz@infradead.org, acme@kernel.org, eranian@google.com, ak@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] perf: Add PERF_SAMPLE_PHYS_ADDR Message-ID: <20160107083319.GF20434@krava.brq.redhat.com> References: <1452078277-15520-1-git-send-email-kan.liang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1452078277-15520-1-git-send-email-kan.liang@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 06, 2016 at 06:04:30AM -0500, kan.liang@intel.com wrote: > From: Kan Liang > > For understanding how the workload maps to memory channels and hardware > behavior, it's useful to collect address maps with physical addresses. > This is not intended for detecting page sharing (which can be already > done using the mmap inode), but for lower level hardware behavior > studies. > Perf supports load latency/DLA which can only collect virtual addresses. > This patch add a new sample type PERF_SAMPLE_PHYS_ADDR to expose the > physical addresses. > For kernel direct mapping addresses, the patch uses virt_to_phys to > convert the virtual addresses from DLA to physical address. > For user virtual addresses, __get_user_pages_fast is used to walk the > pages tables for user physical address. > This does not work for vmalloc addresses. Right now these are not > resolved, but code to do that could be added. > For security, the physical address can only be exposed to root or > privileged user. > > Signed-off-by: Kan Liang > --- > arch/x86/kernel/cpu/perf_event.h | 2 +- > arch/x86/kernel/cpu/perf_event_intel_ds.c | 23 +++++++++++++++++++++++ > include/linux/perf_event.h | 3 +++ > include/uapi/linux/perf_event.h | 4 +++- > kernel/events/core.c | 11 +++++++++++ > 5 files changed, 41 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h > index 799e6bd..164de68 100644 > --- a/arch/x86/kernel/cpu/perf_event.h > +++ b/arch/x86/kernel/cpu/perf_event.h > @@ -90,7 +90,7 @@ struct amd_nb { > (PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_ADDR | \ > PERF_SAMPLE_ID | PERF_SAMPLE_CPU | PERF_SAMPLE_STREAM_ID | \ > PERF_SAMPLE_DATA_SRC | PERF_SAMPLE_IDENTIFIER | \ > - PERF_SAMPLE_TRANSACTION) > + PERF_SAMPLE_TRANSACTION | PERF_SAMPLE_PHYS_ADDR) could you please add some probe code to detect kernel support, so we get some sensible error message [jolsa@krava perf]$ ./perf mem -p record ls Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cpu/mem-loads/pp). /bin/dmesg may provide additional information. No CONFIG_PERF_EVENTS=y kernel support configured? thanks, jirka