From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751860AbeEDJyj (ORCPT ); Fri, 4 May 2018 05:54:39 -0400 Received: from 9pmail.ess.barracuda.com ([64.235.154.211]:47872 "EHLO 9pmail.ess.barracuda.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751613AbeEDJyi (ORCPT ); Fri, 4 May 2018 05:54:38 -0400 Subject: Re: [RFC PATCH] MIPS: Oprofile: Drop support To: Robert Richter CC: James Hogan , Ralf Baechle , , Huacai Chen , , Jiaxun Yang , Krzysztof Kozlowski , Robert Richter , References: <1524574554-7451-1-git-send-email-matt.redfearn@mips.com> <20180424130511.GB28813@saruman> <5e464a40-4e4d-dde4-b5b5-ceb637dc5f38@mips.com> <20180504093002.GC4493@rric.localdomain> From: Matt Redfearn Message-ID: Date: Fri, 4 May 2018 10:54:32 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180504093002.GC4493@rric.localdomain> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.155.41] X-ClientProxiedBy: mipsdag02.mipstec.com (10.20.40.47) To mipsdag02.mipstec.com (10.20.40.47) X-BESS-ID: 1525427651-321459-17908-26004-1 X-BESS-VER: 2018.5-r1804261738 X-BESS-Apparent-Source-IP: 12.201.5.32 X-BESS-Outbound-Spam-Score: 0.00 X-BESS-Outbound-Spam-Report: Code version 3.2, rules version 3.2.2.192686 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------- 0.00 BSF_BESS_OUTBOUND META: BESS Outbound X-BESS-Outbound-Spam-Status: SCORE=0.00 using account:ESS59374 scores of KILL_LEVEL=7.0 tests=BSF_BESS_OUTBOUND X-BESS-BRTS-Status: 1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Robert, On 04/05/18 10:30, Robert Richter wrote: > On 24.04.18 14:15:58, Matt Redfearn wrote: >> On 24/04/18 14:05, James Hogan wrote: >>> On Tue, Apr 24, 2018 at 01:55:54PM +0100, Matt Redfearn wrote: >>>> Since it appears that MIPS oprofile support is currently broken, core >>>> oprofile is not getting many updates and not as many architectures >>>> implement support for it compared to perf, remove the MIPS support. >>> >>> That sounds reasonable to me. Any idea how long its been broken? >> >> Sorry, not yet. I haven't yet looked into where/how it's broken that would >> narrow that down... > > oprofile moved to perf syscall as kernel i/f with version 1.0.0. The OK interesting. I guess this was the point at which MIPS' current Kconfig rule which only allows building oprofile or perf into a kernel broke oprofile userspace. > opcontrol script that was using the oprofile kernel i/f was removed: > > https://sourceforge.net/p/oprofile/oprofile/ci/0c142c3a096d3e9ec42cc9b0ddad994fea60d135/ > > Thus, cpus that do not support the perf syscall are no longer > supported by 1.x releases. > > https://sourceforge.net/p/oprofile/oprofile/ci/797d01dea0b82dbbdb0c21112a3de75990e011d2/ > > For those remainings there is still version 0.9.x available (tagged > PRE_RELEASE_1_0). > > I am undecided whether removing oprofile kernel i/f falls under the > rule of "never break user space" here. Strictly seen, yes it breaks > those remainings. So if the perf syscall is not available as an > alternative, the oprofile kernel support shouldn't be removed. perf is available for MIPS and supports many more CPU types than oprofile. oprofile userspace seemingly has been broken since 1.0.0 - removing oprofile support from the MIPS kernel would not break it more thatn it already is, but of course it would be better to fix it - if it is still useful and people still use it. That is the question that I was looking for answers for with this RFC - whether to spend the time & effort to fix oprofile, or if it can be removed since everyone uses perf. Thanks, Matt > > -Robert > From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 9pmail.ess.barracuda.com ([64.235.154.211]:39277 "EHLO 9pmail.ess.barracuda.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23991783AbeEDJydKylZN (ORCPT ); Fri, 4 May 2018 11:54:33 +0200 Subject: Re: [RFC PATCH] MIPS: Oprofile: Drop support References: <1524574554-7451-1-git-send-email-matt.redfearn@mips.com> <20180424130511.GB28813@saruman> <5e464a40-4e4d-dde4-b5b5-ceb637dc5f38@mips.com> <20180504093002.GC4493@rric.localdomain> From: Matt Redfearn Message-ID: Date: Fri, 4 May 2018 10:54:32 +0100 MIME-Version: 1.0 In-Reply-To: <20180504093002.GC4493@rric.localdomain> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: Robert Richter Cc: James Hogan , Ralf Baechle , linux-mips@linux-mips.org, Huacai Chen , linux-kernel@vger.kernel.org, Jiaxun Yang , Krzysztof Kozlowski , Robert Richter , oprofile-list@lists.sf.net Message-ID: <20180504095432._a0J18nGFuziqs6tC6XvLXSbLmjooNrckoVaaCjDwS8@z> Hi Robert, On 04/05/18 10:30, Robert Richter wrote: > On 24.04.18 14:15:58, Matt Redfearn wrote: >> On 24/04/18 14:05, James Hogan wrote: >>> On Tue, Apr 24, 2018 at 01:55:54PM +0100, Matt Redfearn wrote: >>>> Since it appears that MIPS oprofile support is currently broken, core >>>> oprofile is not getting many updates and not as many architectures >>>> implement support for it compared to perf, remove the MIPS support. >>> >>> That sounds reasonable to me. Any idea how long its been broken? >> >> Sorry, not yet. I haven't yet looked into where/how it's broken that would >> narrow that down... > > oprofile moved to perf syscall as kernel i/f with version 1.0.0. The OK interesting. I guess this was the point at which MIPS' current Kconfig rule which only allows building oprofile or perf into a kernel broke oprofile userspace. > opcontrol script that was using the oprofile kernel i/f was removed: > > https://sourceforge.net/p/oprofile/oprofile/ci/0c142c3a096d3e9ec42cc9b0ddad994fea60d135/ > > Thus, cpus that do not support the perf syscall are no longer > supported by 1.x releases. > > https://sourceforge.net/p/oprofile/oprofile/ci/797d01dea0b82dbbdb0c21112a3de75990e011d2/ > > For those remainings there is still version 0.9.x available (tagged > PRE_RELEASE_1_0). > > I am undecided whether removing oprofile kernel i/f falls under the > rule of "never break user space" here. Strictly seen, yes it breaks > those remainings. So if the perf syscall is not available as an > alternative, the oprofile kernel support shouldn't be removed. perf is available for MIPS and supports many more CPU types than oprofile. oprofile userspace seemingly has been broken since 1.0.0 - removing oprofile support from the MIPS kernel would not break it more thatn it already is, but of course it would be better to fix it - if it is still useful and people still use it. That is the question that I was looking for answers for with this RFC - whether to spend the time & effort to fix oprofile, or if it can be removed since everyone uses perf. Thanks, Matt > > -Robert >