From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BC17C3279B for ; Wed, 11 Jul 2018 00:47:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC1B820936 for ; Wed, 11 Jul 2018 00:47:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC1B820936 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732332AbeGKAst (ORCPT ); Tue, 10 Jul 2018 20:48:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:51240 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732275AbeGKAst (ORCPT ); Tue, 10 Jul 2018 20:48:49 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D0B9A208E5; Wed, 11 Jul 2018 00:47:09 +0000 (UTC) Date: Tue, 10 Jul 2018 20:47:07 -0400 From: Steven Rostedt To: Joel Fernandes Cc: linux-kernel@vger.kernel.org, Andy Shevchenko , Boqun Feng , Byungchul Park , Ingo Molnar , Julia Cartwright , linux-kselftest@vger.kernel.org, Masami Hiramatsu , Mathieu Desnoyers , Namhyung Kim , Paul McKenney , Peter Zijlstra , Thomas Glexiner , Tom Zanussi Subject: Re: [PATCH v9 6/7] lib: Add module to simulate atomic sections for testing preemptoff tracers Message-ID: <20180710204707.2fbaef87@gandalf.local.home> In-Reply-To: <20180628182149.226164-7-joel@joelfernandes.org> References: <20180628182149.226164-1-joel@joelfernandes.org> <20180628182149.226164-7-joel@joelfernandes.org> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 28 Jun 2018 11:21:48 -0700 Joel Fernandes wrote: > From: "Joel Fernandes (Google)" > > In this patch we introduce a test module for simulating a long atomic > section in the kernel which the preemptoff or irqsoff tracers can > detect. This module is to be used only for test purposes and is default > disabled. > > Following is the expected output (only briefly shown) that can be parsed > to verify that the tracers are working correctly. We will use this from > the kselftests in future patches. > > For the preemptoff tracer: > > echo preemptoff > /d/tracing/current_tracer > sleep 1 > insmod ./test_atomic_sections.ko atomic_mode=preempt atomic_time=500000 > sleep 1 > bash-4.3# cat /d/tracing/trace > preempt -1066 2...2 0us@: atomic_sect_run <-atomic_sect_run > preempt -1066 2...2 500002us : atomic_sect_run <-atomic_sect_run > preempt -1066 2...2 500004us : tracer_preempt_on <-atomic_sect_run > preempt -1066 2...2 500012us : > => kthread > => ret_from_fork > > For the irqsoff tracer: > > echo irqsoff > /d/tracing/current_tracer > sleep 1 > insmod ./test_atomic_sections.ko atomic_mode=irq atomic_time=500000 > sleep 1 > bash-4.3# cat /d/tracing/trace > irq dis -1069 1d..1 0us@: atomic_sect_run > irq dis -1069 1d..1 500001us : atomic_sect_run > irq dis -1069 1d..1 500002us : tracer_hardirqs_on <-atomic_sect_run > irq dis -1069 1d..1 500005us : > => ret_from_fork > > Co-developed-by: Erick Reyes > Cc: Andy Shevchenko > Reviewed-by: Andy Shevchenko > Signed-off-by: Joel Fernandes (Google) > --- > lib/Kconfig.debug | 8 ++++ > lib/Makefile | 1 + > lib/test_atomic_sections.c | 77 ++++++++++++++++++++++++++++++++++++++ I think this code should reside in kernel/trace directory. I already have modules there. See the ring_buffer_benchmark code and the test module for mmio tracer. > 3 files changed, 86 insertions(+) > create mode 100644 lib/test_atomic_sections.c > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 8838d1158d19..622c90e1e066 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1956,6 +1956,14 @@ config TEST_KMOD > > If unsure, say N. > > +config TEST_ATOMIC_SECTIONS > + tristate "Simulate atomic sections for tracers to detect" Hmm, I don't like this title. It's not very obvious to what it is about. What about "Preempt / IRQ disable delay thread to test latency tracers" ? Or something along those lines. > + depends on m > + help > + Select this option to build a test module that can help test atomic > + sections by simulating them with a duration supplied as a module > + parameter. Preempt disable and irq disable modes can be requested. "If unsure say N" > + > config TEST_DEBUG_VIRTUAL > tristate "Test CONFIG_DEBUG_VIRTUAL feature" > depends on DEBUG_VIRTUAL > diff --git a/lib/Makefile b/lib/Makefile > index 90dc5520b784..7831e747bf72 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -44,6 +44,7 @@ obj-y += string_helpers.o > obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o > obj-y += hexdump.o > obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o > +obj-$(CONFIG_TEST_ATOMIC_SECTIONS) += test_atomic_sections.o > obj-y += kstrtox.o > obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o > obj-$(CONFIG_TEST_BPF) += test_bpf.o > diff --git a/lib/test_atomic_sections.c b/lib/test_atomic_sections.c > new file mode 100644 > index 000000000000..1eef518f0974 > --- /dev/null > +++ b/lib/test_atomic_sections.c > @@ -0,0 +1,77 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Atomic section emulation test module > + * > + * Emulates atomic sections by disabling IRQs or preemption > + * and doing a busy wait for a specified amount of time. > + * This can be used for testing of different atomic section > + * tracers such as irqsoff tracers. > + * > + * (c) 2018. Google LLC > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static ulong atomic_time = 100; > +static char atomic_mode[10] = "irq"; > + > +module_param_named(atomic_time, atomic_time, ulong, S_IRUGO); > +module_param_string(atomic_mode, atomic_mode, 10, S_IRUGO); > +MODULE_PARM_DESC(atomic_time, "Period in microseconds (100 uS default)"); It's not a "Period", it's a delay. "Length of time in critical section" > +MODULE_PARM_DESC(atomic_mode, "Mode of the test such as preempt or irq (default irq)"); "Mode of the test: preempt or irq disabled (default irq)" > + > +static void busy_wait(ulong time) > +{ > + ktime_t start, end; > + start = ktime_get(); > + do { > + end = ktime_get(); > + if (kthread_should_stop()) > + break; > + } while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000)); > +} > + > +int atomic_sect_run(void *data) > +{ > + unsigned long flags; > + > + if (!strcmp(atomic_mode, "irq")) { > + local_irq_save(flags); > + busy_wait(atomic_time); > + local_irq_restore(flags); > + } else if (!strcmp(atomic_mode, "preempt")) { > + preempt_disable(); > + busy_wait(atomic_time); > + preempt_enable(); > + } So this is a one shot deal? That should be explained somewhere, probably in the config help message. In fact, I think the config help message should show how to use this. -- Steve > + > + return 0; > +} > + > +static int __init atomic_sect_init(void) > +{ > + char task_name[50]; > + struct task_struct *test_task; > + > + snprintf(task_name, sizeof(task_name), "%s_test", atomic_mode); > + > + test_task = kthread_run(atomic_sect_run, NULL, task_name); > + return PTR_ERR_OR_ZERO(test_task); > +} > + > +static void __exit atomic_sect_exit(void) > +{ > + return; > +} > + > +module_init(atomic_sect_init) > +module_exit(atomic_sect_exit) > +MODULE_LICENSE("GPL v2"); From mboxrd@z Thu Jan 1 00:00:00 1970 From: rostedt at goodmis.org (Steven Rostedt) Date: Tue, 10 Jul 2018 20:47:07 -0400 Subject: [PATCH v9 6/7] lib: Add module to simulate atomic sections for testing preemptoff tracers In-Reply-To: <20180628182149.226164-7-joel@joelfernandes.org> References: <20180628182149.226164-1-joel@joelfernandes.org> <20180628182149.226164-7-joel@joelfernandes.org> Message-ID: <20180710204707.2fbaef87@gandalf.local.home> On Thu, 28 Jun 2018 11:21:48 -0700 Joel Fernandes wrote: > From: "Joel Fernandes (Google)" > > In this patch we introduce a test module for simulating a long atomic > section in the kernel which the preemptoff or irqsoff tracers can > detect. This module is to be used only for test purposes and is default > disabled. > > Following is the expected output (only briefly shown) that can be parsed > to verify that the tracers are working correctly. We will use this from > the kselftests in future patches. > > For the preemptoff tracer: > > echo preemptoff > /d/tracing/current_tracer > sleep 1 > insmod ./test_atomic_sections.ko atomic_mode=preempt atomic_time=500000 > sleep 1 > bash-4.3# cat /d/tracing/trace > preempt -1066 2...2 0us@: atomic_sect_run <-atomic_sect_run > preempt -1066 2...2 500002us : atomic_sect_run <-atomic_sect_run > preempt -1066 2...2 500004us : tracer_preempt_on <-atomic_sect_run > preempt -1066 2...2 500012us : > => kthread > => ret_from_fork > > For the irqsoff tracer: > > echo irqsoff > /d/tracing/current_tracer > sleep 1 > insmod ./test_atomic_sections.ko atomic_mode=irq atomic_time=500000 > sleep 1 > bash-4.3# cat /d/tracing/trace > irq dis -1069 1d..1 0us@: atomic_sect_run > irq dis -1069 1d..1 500001us : atomic_sect_run > irq dis -1069 1d..1 500002us : tracer_hardirqs_on <-atomic_sect_run > irq dis -1069 1d..1 500005us : > => ret_from_fork > > Co-developed-by: Erick Reyes > Cc: Andy Shevchenko > Reviewed-by: Andy Shevchenko > Signed-off-by: Joel Fernandes (Google) > --- > lib/Kconfig.debug | 8 ++++ > lib/Makefile | 1 + > lib/test_atomic_sections.c | 77 ++++++++++++++++++++++++++++++++++++++ I think this code should reside in kernel/trace directory. I already have modules there. See the ring_buffer_benchmark code and the test module for mmio tracer. > 3 files changed, 86 insertions(+) > create mode 100644 lib/test_atomic_sections.c > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 8838d1158d19..622c90e1e066 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1956,6 +1956,14 @@ config TEST_KMOD > > If unsure, say N. > > +config TEST_ATOMIC_SECTIONS > + tristate "Simulate atomic sections for tracers to detect" Hmm, I don't like this title. It's not very obvious to what it is about. What about "Preempt / IRQ disable delay thread to test latency tracers" ? Or something along those lines. > + depends on m > + help > + Select this option to build a test module that can help test atomic > + sections by simulating them with a duration supplied as a module > + parameter. Preempt disable and irq disable modes can be requested. "If unsure say N" > + > config TEST_DEBUG_VIRTUAL > tristate "Test CONFIG_DEBUG_VIRTUAL feature" > depends on DEBUG_VIRTUAL > diff --git a/lib/Makefile b/lib/Makefile > index 90dc5520b784..7831e747bf72 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -44,6 +44,7 @@ obj-y += string_helpers.o > obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o > obj-y += hexdump.o > obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o > +obj-$(CONFIG_TEST_ATOMIC_SECTIONS) += test_atomic_sections.o > obj-y += kstrtox.o > obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o > obj-$(CONFIG_TEST_BPF) += test_bpf.o > diff --git a/lib/test_atomic_sections.c b/lib/test_atomic_sections.c > new file mode 100644 > index 000000000000..1eef518f0974 > --- /dev/null > +++ b/lib/test_atomic_sections.c > @@ -0,0 +1,77 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Atomic section emulation test module > + * > + * Emulates atomic sections by disabling IRQs or preemption > + * and doing a busy wait for a specified amount of time. > + * This can be used for testing of different atomic section > + * tracers such as irqsoff tracers. > + * > + * (c) 2018. Google LLC > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static ulong atomic_time = 100; > +static char atomic_mode[10] = "irq"; > + > +module_param_named(atomic_time, atomic_time, ulong, S_IRUGO); > +module_param_string(atomic_mode, atomic_mode, 10, S_IRUGO); > +MODULE_PARM_DESC(atomic_time, "Period in microseconds (100 uS default)"); It's not a "Period", it's a delay. "Length of time in critical section" > +MODULE_PARM_DESC(atomic_mode, "Mode of the test such as preempt or irq (default irq)"); "Mode of the test: preempt or irq disabled (default irq)" > + > +static void busy_wait(ulong time) > +{ > + ktime_t start, end; > + start = ktime_get(); > + do { > + end = ktime_get(); > + if (kthread_should_stop()) > + break; > + } while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000)); > +} > + > +int atomic_sect_run(void *data) > +{ > + unsigned long flags; > + > + if (!strcmp(atomic_mode, "irq")) { > + local_irq_save(flags); > + busy_wait(atomic_time); > + local_irq_restore(flags); > + } else if (!strcmp(atomic_mode, "preempt")) { > + preempt_disable(); > + busy_wait(atomic_time); > + preempt_enable(); > + } So this is a one shot deal? That should be explained somewhere, probably in the config help message. In fact, I think the config help message should show how to use this. -- Steve > + > + return 0; > +} > + > +static int __init atomic_sect_init(void) > +{ > + char task_name[50]; > + struct task_struct *test_task; > + > + snprintf(task_name, sizeof(task_name), "%s_test", atomic_mode); > + > + test_task = kthread_run(atomic_sect_run, NULL, task_name); > + return PTR_ERR_OR_ZERO(test_task); > +} > + > +static void __exit atomic_sect_exit(void) > +{ > + return; > +} > + > +module_init(atomic_sect_init) > +module_exit(atomic_sect_exit) > +MODULE_LICENSE("GPL v2"); -- 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: rostedt@goodmis.org (Steven Rostedt) Date: Tue, 10 Jul 2018 20:47:07 -0400 Subject: [PATCH v9 6/7] lib: Add module to simulate atomic sections for testing preemptoff tracers In-Reply-To: <20180628182149.226164-7-joel@joelfernandes.org> References: <20180628182149.226164-1-joel@joelfernandes.org> <20180628182149.226164-7-joel@joelfernandes.org> Message-ID: <20180710204707.2fbaef87@gandalf.local.home> Content-Type: text/plain; charset="UTF-8" Message-ID: <20180711004707.dVNPKpEHgUvfcvwAaI0aRIxEOu91ql_w2urwjAiPrSE@z> On Thu, 28 Jun 2018 11:21:48 -0700 Joel Fernandes wrote: > From: "Joel Fernandes (Google)" > > In this patch we introduce a test module for simulating a long atomic > section in the kernel which the preemptoff or irqsoff tracers can > detect. This module is to be used only for test purposes and is default > disabled. > > Following is the expected output (only briefly shown) that can be parsed > to verify that the tracers are working correctly. We will use this from > the kselftests in future patches. > > For the preemptoff tracer: > > echo preemptoff > /d/tracing/current_tracer > sleep 1 > insmod ./test_atomic_sections.ko atomic_mode=preempt atomic_time=500000 > sleep 1 > bash-4.3# cat /d/tracing/trace > preempt -1066 2...2 0us@: atomic_sect_run <-atomic_sect_run > preempt -1066 2...2 500002us : atomic_sect_run <-atomic_sect_run > preempt -1066 2...2 500004us : tracer_preempt_on <-atomic_sect_run > preempt -1066 2...2 500012us : > => kthread > => ret_from_fork > > For the irqsoff tracer: > > echo irqsoff > /d/tracing/current_tracer > sleep 1 > insmod ./test_atomic_sections.ko atomic_mode=irq atomic_time=500000 > sleep 1 > bash-4.3# cat /d/tracing/trace > irq dis -1069 1d..1 0us@: atomic_sect_run > irq dis -1069 1d..1 500001us : atomic_sect_run > irq dis -1069 1d..1 500002us : tracer_hardirqs_on <-atomic_sect_run > irq dis -1069 1d..1 500005us : > => ret_from_fork > > Co-developed-by: Erick Reyes > Cc: Andy Shevchenko > Reviewed-by: Andy Shevchenko > Signed-off-by: Joel Fernandes (Google) > --- > lib/Kconfig.debug | 8 ++++ > lib/Makefile | 1 + > lib/test_atomic_sections.c | 77 ++++++++++++++++++++++++++++++++++++++ I think this code should reside in kernel/trace directory. I already have modules there. See the ring_buffer_benchmark code and the test module for mmio tracer. > 3 files changed, 86 insertions(+) > create mode 100644 lib/test_atomic_sections.c > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 8838d1158d19..622c90e1e066 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1956,6 +1956,14 @@ config TEST_KMOD > > If unsure, say N. > > +config TEST_ATOMIC_SECTIONS > + tristate "Simulate atomic sections for tracers to detect" Hmm, I don't like this title. It's not very obvious to what it is about. What about "Preempt / IRQ disable delay thread to test latency tracers" ? Or something along those lines. > + depends on m > + help > + Select this option to build a test module that can help test atomic > + sections by simulating them with a duration supplied as a module > + parameter. Preempt disable and irq disable modes can be requested. "If unsure say N" > + > config TEST_DEBUG_VIRTUAL > tristate "Test CONFIG_DEBUG_VIRTUAL feature" > depends on DEBUG_VIRTUAL > diff --git a/lib/Makefile b/lib/Makefile > index 90dc5520b784..7831e747bf72 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -44,6 +44,7 @@ obj-y += string_helpers.o > obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o > obj-y += hexdump.o > obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o > +obj-$(CONFIG_TEST_ATOMIC_SECTIONS) += test_atomic_sections.o > obj-y += kstrtox.o > obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o > obj-$(CONFIG_TEST_BPF) += test_bpf.o > diff --git a/lib/test_atomic_sections.c b/lib/test_atomic_sections.c > new file mode 100644 > index 000000000000..1eef518f0974 > --- /dev/null > +++ b/lib/test_atomic_sections.c > @@ -0,0 +1,77 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Atomic section emulation test module > + * > + * Emulates atomic sections by disabling IRQs or preemption > + * and doing a busy wait for a specified amount of time. > + * This can be used for testing of different atomic section > + * tracers such as irqsoff tracers. > + * > + * (c) 2018. Google LLC > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static ulong atomic_time = 100; > +static char atomic_mode[10] = "irq"; > + > +module_param_named(atomic_time, atomic_time, ulong, S_IRUGO); > +module_param_string(atomic_mode, atomic_mode, 10, S_IRUGO); > +MODULE_PARM_DESC(atomic_time, "Period in microseconds (100 uS default)"); It's not a "Period", it's a delay. "Length of time in critical section" > +MODULE_PARM_DESC(atomic_mode, "Mode of the test such as preempt or irq (default irq)"); "Mode of the test: preempt or irq disabled (default irq)" > + > +static void busy_wait(ulong time) > +{ > + ktime_t start, end; > + start = ktime_get(); > + do { > + end = ktime_get(); > + if (kthread_should_stop()) > + break; > + } while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000)); > +} > + > +int atomic_sect_run(void *data) > +{ > + unsigned long flags; > + > + if (!strcmp(atomic_mode, "irq")) { > + local_irq_save(flags); > + busy_wait(atomic_time); > + local_irq_restore(flags); > + } else if (!strcmp(atomic_mode, "preempt")) { > + preempt_disable(); > + busy_wait(atomic_time); > + preempt_enable(); > + } So this is a one shot deal? That should be explained somewhere, probably in the config help message. In fact, I think the config help message should show how to use this. -- Steve > + > + return 0; > +} > + > +static int __init atomic_sect_init(void) > +{ > + char task_name[50]; > + struct task_struct *test_task; > + > + snprintf(task_name, sizeof(task_name), "%s_test", atomic_mode); > + > + test_task = kthread_run(atomic_sect_run, NULL, task_name); > + return PTR_ERR_OR_ZERO(test_task); > +} > + > +static void __exit atomic_sect_exit(void) > +{ > + return; > +} > + > +module_init(atomic_sect_init) > +module_exit(atomic_sect_exit) > +MODULE_LICENSE("GPL v2"); -- 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