From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751438AbdKURl0 (ORCPT ); Tue, 21 Nov 2017 12:41:26 -0500 Received: from mailout.easymail.ca ([64.68.200.34]:54760 "EHLO mailout.easymail.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751391AbdKURlW (ORCPT ); Tue, 21 Nov 2017 12:41:22 -0500 Reply-To: shuah@kernel.org Subject: Re: [RFC PATCH for 4.15 v3 15/22] rseq: selftests: Provide self-tests To: Mathieu Desnoyers Cc: Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Andy Lutomirski , Dave Watson , linux-kernel , linux-api , Paul Turner , Andrew Morton , Russell King , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Hunter , Andi Kleen , Chris Lameter , Ben Maurer , rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Will Deacon , Michael Kerrisk , linux-kselftest , Shuah Khan , Shuah Khan , Shuah Khan References: <20171121141900.18471-1-mathieu.desnoyers@efficios.com> <20171121141900.18471-16-mathieu.desnoyers@efficios.com> <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> From: Shuah Khan Message-ID: <5b5679fc-a807-8d14-85d0-41a1dd34214e@kernel.org> Date: Tue, 21 Nov 2017 10:40:34 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/21/2017 10:05 AM, Mathieu Desnoyers wrote: > ----- On Nov 21, 2017, at 10:34 AM, shuah shuah@kernel.org wrote: > > [...] >>> --- >>> MAINTAINERS | 1 + >>> tools/testing/selftests/Makefile | 1 + >>> tools/testing/selftests/rseq/.gitignore | 4 + >> >> Thanks for the .gitignore files. It is commonly missed change, I end >> up adding one to clean things up after tests get in. > > I'm used to receive patches where contributors forget to add new files > to gitignore within my own projects, which may contribute to my awareness > of this pain point. :) > > [...] > >>> + >>> +void *test_percpu_inc_thread(void *arg) >>> +{ >>> + struct inc_thread_test_data *thread_data = arg; >>> + struct inc_test_data *data = thread_data->data; >>> + long long i, reps; >>> + >>> + if (!opt_disable_rseq && thread_data->reg >>> + && rseq_register_current_thread()) >>> + abort(); >>> + reps = thread_data->reps; >>> + for (i = 0; i < reps; i++) { >>> + int cpu, ret; >>> + >>> +#ifndef SKIP_FASTPATH >>> + /* Try fast path. */ >>> + cpu = rseq_cpu_start(); >>> + ret = rseq_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + goto next; >>> +#endif >> >> So the test needs to compiled with this enabled? I think it would be better >> to make this an argument to be abel to select at test start time as opposed >> to making this compile time option. Remember that these tests get run in >> automated test rings. Making this a compile time otpion pertty much ensures >> that this path will not be tested. >> >> So I would reccommend adding a paratemer. >> >>> + slowpath: >>> + __attribute__((unused)); >>> + for (;;) { >>> + /* Fallback on cpu_opv system call. */ >>> + cpu = rseq_current_cpu(); >>> + ret = cpu_op_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + break; >>> + assert(ret >= 0 || errno == EAGAIN); >>> + } >>> + next: >>> + __attribute__((unused)); >>> +#ifndef BENCHMARK >>> + if (i != 0 && !(i % (reps / 10))) >>> + printf_verbose("tid %d: count %lld\n", (int) gettid(), i); >>> +#endif >> >> Same comment as before. Avoid compile time options. > > The goal of those compiler define are to generate the altered code without > adding branches into the fast-paths. That makes sense. You are looking to not add any overhead. > > Here is an alternative solution that should take care of your concern: I'll > build multiple targets for param_test.c: > > param_test > param_test_skip_fastpath (built with -DSKIP_FASTPATH) > param_test_benchmark (build with -DBENCHMARK) > > I'll update run_param_test.sh to run both param_test and param_test_skip_fastpath. > > Note that "param_test_benchmark" is only useful for benchmarking, > so I don't plan to run it from run_param_test.sh which is meant > to track regressions. > > Is that approach OK with you ? > Yes. This approach addresses my concern about coverage for both paths. thanks, -- Shuah From mboxrd@z Thu Jan 1 00:00:00 1970 From: shuah at kernel.org (Shuah Khan) Date: Tue, 21 Nov 2017 10:40:34 -0700 Subject: [Linux-kselftest-mirror] [RFC PATCH for 4.15 v3 15/22] rseq: selftests: Provide self-tests In-Reply-To: <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> References: <20171121141900.18471-1-mathieu.desnoyers@efficios.com> <20171121141900.18471-16-mathieu.desnoyers@efficios.com> <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> Message-ID: <5b5679fc-a807-8d14-85d0-41a1dd34214e@kernel.org> On 11/21/2017 10:05 AM, Mathieu Desnoyers wrote: > ----- On Nov 21, 2017, at 10:34 AM, shuah shuah at kernel.org wrote: > > [...] >>> --- >>> MAINTAINERS | 1 + >>> tools/testing/selftests/Makefile | 1 + >>> tools/testing/selftests/rseq/.gitignore | 4 + >> >> Thanks for the .gitignore files. It is commonly missed change, I end >> up adding one to clean things up after tests get in. > > I'm used to receive patches where contributors forget to add new files > to gitignore within my own projects, which may contribute to my awareness > of this pain point. :) > > [...] > >>> + >>> +void *test_percpu_inc_thread(void *arg) >>> +{ >>> + struct inc_thread_test_data *thread_data = arg; >>> + struct inc_test_data *data = thread_data->data; >>> + long long i, reps; >>> + >>> + if (!opt_disable_rseq && thread_data->reg >>> + && rseq_register_current_thread()) >>> + abort(); >>> + reps = thread_data->reps; >>> + for (i = 0; i < reps; i++) { >>> + int cpu, ret; >>> + >>> +#ifndef SKIP_FASTPATH >>> + /* Try fast path. */ >>> + cpu = rseq_cpu_start(); >>> + ret = rseq_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + goto next; >>> +#endif >> >> So the test needs to compiled with this enabled? I think it would be better >> to make this an argument to be abel to select at test start time as opposed >> to making this compile time option. Remember that these tests get run in >> automated test rings. Making this a compile time otpion pertty much ensures >> that this path will not be tested. >> >> So I would reccommend adding a paratemer. >> >>> + slowpath: >>> + __attribute__((unused)); >>> + for (;;) { >>> + /* Fallback on cpu_opv system call. */ >>> + cpu = rseq_current_cpu(); >>> + ret = cpu_op_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + break; >>> + assert(ret >= 0 || errno == EAGAIN); >>> + } >>> + next: >>> + __attribute__((unused)); >>> +#ifndef BENCHMARK >>> + if (i != 0 && !(i % (reps / 10))) >>> + printf_verbose("tid %d: count %lld\n", (int) gettid(), i); >>> +#endif >> >> Same comment as before. Avoid compile time options. > > The goal of those compiler define are to generate the altered code without > adding branches into the fast-paths. That makes sense. You are looking to not add any overhead. > > Here is an alternative solution that should take care of your concern: I'll > build multiple targets for param_test.c: > > param_test > param_test_skip_fastpath (built with -DSKIP_FASTPATH) > param_test_benchmark (build with -DBENCHMARK) > > I'll update run_param_test.sh to run both param_test and param_test_skip_fastpath. > > Note that "param_test_benchmark" is only useful for benchmarking, > so I don't plan to run it from run_param_test.sh which is meant > to track regressions. > > Is that approach OK with you ? > Yes. This approach addresses my concern about coverage for both paths. thanks, -- Shuah -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: shuah@kernel.org (Shuah Khan) Date: Tue, 21 Nov 2017 10:40:34 -0700 Subject: [Linux-kselftest-mirror] [RFC PATCH for 4.15 v3 15/22] rseq: selftests: Provide self-tests In-Reply-To: <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> References: <20171121141900.18471-1-mathieu.desnoyers@efficios.com> <20171121141900.18471-16-mathieu.desnoyers@efficios.com> <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> Message-ID: <5b5679fc-a807-8d14-85d0-41a1dd34214e@kernel.org> Content-Type: text/plain; charset="UTF-8" Message-ID: <20171121174034.hVRiQIhgP4EB5O9metluOVT1SlvZc30UAPfHmzvwsE0@z> On 11/21/2017 10:05 AM, Mathieu Desnoyers wrote: > ----- On Nov 21, 2017,@10:34 AM, shuah shuah@kernel.org wrote: > > [...] >>> --- >>> MAINTAINERS | 1 + >>> tools/testing/selftests/Makefile | 1 + >>> tools/testing/selftests/rseq/.gitignore | 4 + >> >> Thanks for the .gitignore files. It is commonly missed change, I end >> up adding one to clean things up after tests get in. > > I'm used to receive patches where contributors forget to add new files > to gitignore within my own projects, which may contribute to my awareness > of this pain point. :) > > [...] > >>> + >>> +void *test_percpu_inc_thread(void *arg) >>> +{ >>> + struct inc_thread_test_data *thread_data = arg; >>> + struct inc_test_data *data = thread_data->data; >>> + long long i, reps; >>> + >>> + if (!opt_disable_rseq && thread_data->reg >>> + && rseq_register_current_thread()) >>> + abort(); >>> + reps = thread_data->reps; >>> + for (i = 0; i < reps; i++) { >>> + int cpu, ret; >>> + >>> +#ifndef SKIP_FASTPATH >>> + /* Try fast path. */ >>> + cpu = rseq_cpu_start(); >>> + ret = rseq_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + goto next; >>> +#endif >> >> So the test needs to compiled with this enabled? I think it would be better >> to make this an argument to be abel to select at test start time as opposed >> to making this compile time option. Remember that these tests get run in >> automated test rings. Making this a compile time otpion pertty much ensures >> that this path will not be tested. >> >> So I would reccommend adding a paratemer. >> >>> + slowpath: >>> + __attribute__((unused)); >>> + for (;;) { >>> + /* Fallback on cpu_opv system call. */ >>> + cpu = rseq_current_cpu(); >>> + ret = cpu_op_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + break; >>> + assert(ret >= 0 || errno == EAGAIN); >>> + } >>> + next: >>> + __attribute__((unused)); >>> +#ifndef BENCHMARK >>> + if (i != 0 && !(i % (reps / 10))) >>> + printf_verbose("tid %d: count %lld\n", (int) gettid(), i); >>> +#endif >> >> Same comment as before. Avoid compile time options. > > The goal of those compiler define are to generate the altered code without > adding branches into the fast-paths. That makes sense. You are looking to not add any overhead. > > Here is an alternative solution that should take care of your concern: I'll > build multiple targets for param_test.c: > > param_test > param_test_skip_fastpath (built with -DSKIP_FASTPATH) > param_test_benchmark (build with -DBENCHMARK) > > I'll update run_param_test.sh to run both param_test and param_test_skip_fastpath. > > Note that "param_test_benchmark" is only useful for benchmarking, > so I don't plan to run it from run_param_test.sh which is meant > to track regressions. > > Is that approach OK with you ? > Yes. This approach addresses my concern about coverage for both paths. thanks, -- Shuah -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shuah Khan Subject: Re: [RFC PATCH for 4.15 v3 15/22] rseq: selftests: Provide self-tests Date: Tue, 21 Nov 2017 10:40:34 -0700 Message-ID: <5b5679fc-a807-8d14-85d0-41a1dd34214e@kernel.org> References: <20171121141900.18471-1-mathieu.desnoyers@efficios.com> <20171121141900.18471-16-mathieu.desnoyers@efficios.com> <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> Reply-To: shuah@kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1823512285.19395.1511283912405.JavaMail.zimbra@efficios.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Mathieu Desnoyers Cc: Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Andy Lutomirski , Dave Watson , linux-kernel , linux-api , Paul Turner , Andrew Morton , Russell King , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Hunter , Andi Kleen , Chris Lameter , Ben Maurer , rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas List-Id: linux-api@vger.kernel.org On 11/21/2017 10:05 AM, Mathieu Desnoyers wrote: > ----- On Nov 21, 2017, at 10:34 AM, shuah shuah@kernel.org wrote: > > [...] >>> --- >>> MAINTAINERS | 1 + >>> tools/testing/selftests/Makefile | 1 + >>> tools/testing/selftests/rseq/.gitignore | 4 + >> >> Thanks for the .gitignore files. It is commonly missed change, I end >> up adding one to clean things up after tests get in. > > I'm used to receive patches where contributors forget to add new files > to gitignore within my own projects, which may contribute to my awareness > of this pain point. :) > > [...] > >>> + >>> +void *test_percpu_inc_thread(void *arg) >>> +{ >>> + struct inc_thread_test_data *thread_data = arg; >>> + struct inc_test_data *data = thread_data->data; >>> + long long i, reps; >>> + >>> + if (!opt_disable_rseq && thread_data->reg >>> + && rseq_register_current_thread()) >>> + abort(); >>> + reps = thread_data->reps; >>> + for (i = 0; i < reps; i++) { >>> + int cpu, ret; >>> + >>> +#ifndef SKIP_FASTPATH >>> + /* Try fast path. */ >>> + cpu = rseq_cpu_start(); >>> + ret = rseq_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + goto next; >>> +#endif >> >> So the test needs to compiled with this enabled? I think it would be better >> to make this an argument to be abel to select at test start time as opposed >> to making this compile time option. Remember that these tests get run in >> automated test rings. Making this a compile time otpion pertty much ensures >> that this path will not be tested. >> >> So I would reccommend adding a paratemer. >> >>> + slowpath: >>> + __attribute__((unused)); >>> + for (;;) { >>> + /* Fallback on cpu_opv system call. */ >>> + cpu = rseq_current_cpu(); >>> + ret = cpu_op_addv(&data->c[cpu].count, 1, cpu); >>> + if (likely(!ret)) >>> + break; >>> + assert(ret >= 0 || errno == EAGAIN); >>> + } >>> + next: >>> + __attribute__((unused)); >>> +#ifndef BENCHMARK >>> + if (i != 0 && !(i % (reps / 10))) >>> + printf_verbose("tid %d: count %lld\n", (int) gettid(), i); >>> +#endif >> >> Same comment as before. Avoid compile time options. > > The goal of those compiler define are to generate the altered code without > adding branches into the fast-paths. That makes sense. You are looking to not add any overhead. > > Here is an alternative solution that should take care of your concern: I'll > build multiple targets for param_test.c: > > param_test > param_test_skip_fastpath (built with -DSKIP_FASTPATH) > param_test_benchmark (build with -DBENCHMARK) > > I'll update run_param_test.sh to run both param_test and param_test_skip_fastpath. > > Note that "param_test_benchmark" is only useful for benchmarking, > so I don't plan to run it from run_param_test.sh which is meant > to track regressions. > > Is that approach OK with you ? > Yes. This approach addresses my concern about coverage for both paths. thanks, -- Shuah