RE: [RFC][PATCH v6]trace,x86: add x86 irq vector tracepoints
Thank you for reviewing my patch. I will update it in accordance with your comment. Seiji > -Original Message- > From: Steven Rostedt [mailto:rost...@goodmis.org] > Sent: Monday, December 17, 2012 10:02 PM > To: Seiji Aguchi > Cc: x...@kernel.org; linux-kernel@vger.kernel.org; H. Peter Anvin > (h...@zytor.com); Thomas Gleixner (t...@linutronix.de); > 'mi...@elte.hu' (mi...@elte.hu); Borislav Petkov (b...@alien8.de); Satoru > Moriya; dle-deve...@lists.sourceforge.net; linux- > e...@vger.kernel.org; Luck, Tony (tony.l...@intel.com) > Subject: Re: [RFC][PATCH v6]trace,x86: add x86 irq vector tracepoints > > On Tue, 2012-12-18 at 01:34 +, Seiji Aguchi wrote: > > Change log > > > > v5 -> v6 > > - Rebased to 3.7 > > > > v4 -> v5 > > - Rebased to 3.6.0 > > > > - Introduce a logic switching IDT at enabling/disabling TP time > >so that a time penalty makes a zero when tracepoints are disabled. > >This IDT is created only when CONFIG_TRACEPOINTS is enabled. > > > > - Remove arch_irq_vector_entry/exit and add followings again > >so that we can add each tracepoint in a generic way. > >- error_apic_vector > >- thermal_apic_vector > >- threshold_apic_vector > >- spurious_apic_vector > >- x86_platform_ipi_vector > > > > - Drop nmi tracepoints to begin with apic interrupts and discuss a logic > > switching > >IDT first. > > > > - Move irq_vectors.h in the directory of arch/x86/include/asm/trace because > >I'm not sure if a logic switching IDT is sharable with other > > architectures. > > > > v3 -> v4 > > - Add a latency measurement of each tracepoint > > - Rebased to 3.6-rc6 > > > > v2 -> v3 > > - Remove an invalidate_tlb_vector event because it was replaced by a call > > function vector > >in a following commit. > > > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit; > > h=52aec3308db85f4e9f5c8b9f5dc4fbd0138c6fa4 > > > > v1 -> v2 > > - Modify variable name from irq to vector. > > - Merge arch-specific tracepoints below to an arch_irq_vector_entry/exit. > >- error_apic_vector > >- thermal_apic_vector > >- threshold_apic_vector > >- spurious_apic_vector > >- x86_platform_ipi_vector > > > > [Purpose of this patch] > > > > As Vaibhav explained in the thread below, tracepoints for irq vectors > > are useful. > > > > http://www.spinics.net/lists/mm-commits/msg85707.html > > > > > > The current interrupt traces from irq_handler_entry and > > irq_handler_exit provide when an interrupt is handled. They provide > > good data about when the system has switched to kernel space and how > > it affects the currently running processes. > > > > There are some IRQ vectors which trigger the system into kernel space, > > which are not handled in generic IRQ handlers. Tracing such events > > gives us the information about IRQ interaction with other system events. > > > > The trace also tells where the system is spending its time. We want > > to know which cores are handling interrupts and how they are affecting > > other processes in the system. Also, the trace provides information > > about when the cores are idle and which interrupts are changing that state. > > > > > > On the other hand, my usecase is tracing just local timer event and > > getting a value of instruction pointer. > > > > I suggested to add an argument local timer event to get instruction > > pointer before. > > But there is another way to get it with external module like systemtap. > > So, I don't need to add any argument to irq vector tracepoints now. > > > > [Patch Description] > > > > Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in > > all events. > > But there is an above use case to trace specific irq_vector rather than > > tracing all events. > > In this case, we are concerned about overhead due to unwanted events. > > > > This patch adds following tracepoints instead of introducing > > irq_vector_entry/exit. > > so that we can enable them independently. > >- local_timer_vector > >- reschedule_vector > >- call_function_vector > >- call_function_single_vector > >- irq_work_entry_vector > >- error_apic_vector > >- thermal_apic_vector > >- threshold_apic_vector > >- spurious_apic_vector > >- x86_platform_ipi_vector >
Re: [RFC][PATCH v6]trace,x86: add x86 irq vector tracepoints
On Tue, 2012-12-18 at 01:34 +, Seiji Aguchi wrote: > Change log > > v5 -> v6 > - Rebased to 3.7 > > v4 -> v5 > - Rebased to 3.6.0 > > - Introduce a logic switching IDT at enabling/disabling TP time >so that a time penalty makes a zero when tracepoints are disabled. >This IDT is created only when CONFIG_TRACEPOINTS is enabled. > > - Remove arch_irq_vector_entry/exit and add followings again >so that we can add each tracepoint in a generic way. >- error_apic_vector >- thermal_apic_vector >- threshold_apic_vector >- spurious_apic_vector >- x86_platform_ipi_vector > > - Drop nmi tracepoints to begin with apic interrupts and discuss a logic > switching >IDT first. > > - Move irq_vectors.h in the directory of arch/x86/include/asm/trace because >I'm not sure if a logic switching IDT is sharable with other architectures. > > v3 -> v4 > - Add a latency measurement of each tracepoint > - Rebased to 3.6-rc6 > > v2 -> v3 > - Remove an invalidate_tlb_vector event because it was replaced by a call > function vector >in a following commit. > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=52aec3308db85f4e9f5c8b9f5dc4fbd0138c6fa4 > > v1 -> v2 > - Modify variable name from irq to vector. > - Merge arch-specific tracepoints below to an arch_irq_vector_entry/exit. >- error_apic_vector >- thermal_apic_vector >- threshold_apic_vector >- spurious_apic_vector >- x86_platform_ipi_vector > > [Purpose of this patch] > > As Vaibhav explained in the thread below, tracepoints for irq vectors > are useful. > > http://www.spinics.net/lists/mm-commits/msg85707.html > > > The current interrupt traces from irq_handler_entry and irq_handler_exit > provide when an interrupt is handled. They provide good data about when > the system has switched to kernel space and how it affects the currently > running processes. > > There are some IRQ vectors which trigger the system into kernel space, > which are not handled in generic IRQ handlers. Tracing such events gives > us the information about IRQ interaction with other system events. > > The trace also tells where the system is spending its time. We want to > know which cores are handling interrupts and how they are affecting other > processes in the system. Also, the trace provides information about when > the cores are idle and which interrupts are changing that state. > > > On the other hand, my usecase is tracing just local timer event and > getting a value of instruction pointer. > > I suggested to add an argument local timer event to get instruction pointer > before. > But there is another way to get it with external module like systemtap. > So, I don't need to add any argument to irq vector tracepoints now. > > [Patch Description] > > Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in > all events. > But there is an above use case to trace specific irq_vector rather than > tracing all events. > In this case, we are concerned about overhead due to unwanted events. > > This patch adds following tracepoints instead of introducing > irq_vector_entry/exit. > so that we can enable them independently. >- local_timer_vector >- reschedule_vector >- call_function_vector >- call_function_single_vector >- irq_work_entry_vector >- error_apic_vector >- thermal_apic_vector >- threshold_apic_vector >- spurious_apic_vector >- x86_platform_ipi_vector > > Also, it introduces a logic switching IDT at enabling/disabling time so that > a time penalty makes > a complete zero when tracepoints are disabled. Detailed explanations are as > follows. > - Create new irq handlers inserted tracepoints by using macros. > - Create a new IDT, trace_idt_table, at boot time by duplicating original > IDT, idt table, and >registering the new handers for tracpoints. > - Switch IDT to new one at enabling TP time. > - Restore to an original IDT at disabling TP time. > The new IDT is created only when CONFIG_TRACEPOINTS is enabled to avoid being > used for other purposes. > > Signed-off-by: Seiji Aguchi > --- > arch/x86/include/asm/desc.h | 27 + > arch/x86/include/asm/entry_arch.h| 32 + > arch/x86/include/asm/hw_irq.h| 14 +++ > arch/x86/kernel/Makefile |1 + > arch/x86/kernel/apic/apic.c | 186 > +- > arch/x86/kernel/cpu/mcheck/therm_throt.c | 26 +++-- > arch/x86/kernel/cpu/mcheck/threshold.c | 27 +++-- > arch/x86/kernel/entry_64.S | 33 ++ > arch/x86/kernel/head_64.S|6 + > arch/x86/kernel/irq.c| 44 --- > arch/x86/kernel/irq_work.c | 22 +++- > arch/x86/kernel/irqinit.c|2 + > arch/x86/kernel/smp.c| 68 > 13 files changed, 345 insertions(+),
Re: [RFC][PATCH v6]trace,x86: add x86 irq vector tracepoints
On Tue, 2012-12-18 at 01:34 +, Seiji Aguchi wrote: Change log v5 - v6 - Rebased to 3.7 v4 - v5 - Rebased to 3.6.0 - Introduce a logic switching IDT at enabling/disabling TP time so that a time penalty makes a zero when tracepoints are disabled. This IDT is created only when CONFIG_TRACEPOINTS is enabled. - Remove arch_irq_vector_entry/exit and add followings again so that we can add each tracepoint in a generic way. - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector - Drop nmi tracepoints to begin with apic interrupts and discuss a logic switching IDT first. - Move irq_vectors.h in the directory of arch/x86/include/asm/trace because I'm not sure if a logic switching IDT is sharable with other architectures. v3 - v4 - Add a latency measurement of each tracepoint - Rebased to 3.6-rc6 v2 - v3 - Remove an invalidate_tlb_vector event because it was replaced by a call function vector in a following commit. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=52aec3308db85f4e9f5c8b9f5dc4fbd0138c6fa4 v1 - v2 - Modify variable name from irq to vector. - Merge arch-specific tracepoints below to an arch_irq_vector_entry/exit. - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector [Purpose of this patch] As Vaibhav explained in the thread below, tracepoints for irq vectors are useful. http://www.spinics.net/lists/mm-commits/msg85707.html snip The current interrupt traces from irq_handler_entry and irq_handler_exit provide when an interrupt is handled. They provide good data about when the system has switched to kernel space and how it affects the currently running processes. There are some IRQ vectors which trigger the system into kernel space, which are not handled in generic IRQ handlers. Tracing such events gives us the information about IRQ interaction with other system events. The trace also tells where the system is spending its time. We want to know which cores are handling interrupts and how they are affecting other processes in the system. Also, the trace provides information about when the cores are idle and which interrupts are changing that state. snip On the other hand, my usecase is tracing just local timer event and getting a value of instruction pointer. I suggested to add an argument local timer event to get instruction pointer before. But there is another way to get it with external module like systemtap. So, I don't need to add any argument to irq vector tracepoints now. [Patch Description] Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events. But there is an above use case to trace specific irq_vector rather than tracing all events. In this case, we are concerned about overhead due to unwanted events. This patch adds following tracepoints instead of introducing irq_vector_entry/exit. so that we can enable them independently. - local_timer_vector - reschedule_vector - call_function_vector - call_function_single_vector - irq_work_entry_vector - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector Also, it introduces a logic switching IDT at enabling/disabling time so that a time penalty makes a complete zero when tracepoints are disabled. Detailed explanations are as follows. - Create new irq handlers inserted tracepoints by using macros. - Create a new IDT, trace_idt_table, at boot time by duplicating original IDT, idt table, and registering the new handers for tracpoints. - Switch IDT to new one at enabling TP time. - Restore to an original IDT at disabling TP time. The new IDT is created only when CONFIG_TRACEPOINTS is enabled to avoid being used for other purposes. Signed-off-by: Seiji Aguchi seiji.agu...@hds.com --- arch/x86/include/asm/desc.h | 27 + arch/x86/include/asm/entry_arch.h| 32 + arch/x86/include/asm/hw_irq.h| 14 +++ arch/x86/kernel/Makefile |1 + arch/x86/kernel/apic/apic.c | 186 +- arch/x86/kernel/cpu/mcheck/therm_throt.c | 26 +++-- arch/x86/kernel/cpu/mcheck/threshold.c | 27 +++-- arch/x86/kernel/entry_64.S | 33 ++ arch/x86/kernel/head_64.S|6 + arch/x86/kernel/irq.c| 44 --- arch/x86/kernel/irq_work.c | 22 +++- arch/x86/kernel/irqinit.c|2 + arch/x86/kernel/smp.c| 68 13 files changed, 345 insertions(+), 143 deletions(-) diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index
RE: [RFC][PATCH v6]trace,x86: add x86 irq vector tracepoints
Thank you for reviewing my patch. I will update it in accordance with your comment. Seiji -Original Message- From: Steven Rostedt [mailto:rost...@goodmis.org] Sent: Monday, December 17, 2012 10:02 PM To: Seiji Aguchi Cc: x...@kernel.org; linux-kernel@vger.kernel.org; H. Peter Anvin (h...@zytor.com); Thomas Gleixner (t...@linutronix.de); 'mi...@elte.hu' (mi...@elte.hu); Borislav Petkov (b...@alien8.de); Satoru Moriya; dle-deve...@lists.sourceforge.net; linux- e...@vger.kernel.org; Luck, Tony (tony.l...@intel.com) Subject: Re: [RFC][PATCH v6]trace,x86: add x86 irq vector tracepoints On Tue, 2012-12-18 at 01:34 +, Seiji Aguchi wrote: Change log v5 - v6 - Rebased to 3.7 v4 - v5 - Rebased to 3.6.0 - Introduce a logic switching IDT at enabling/disabling TP time so that a time penalty makes a zero when tracepoints are disabled. This IDT is created only when CONFIG_TRACEPOINTS is enabled. - Remove arch_irq_vector_entry/exit and add followings again so that we can add each tracepoint in a generic way. - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector - Drop nmi tracepoints to begin with apic interrupts and discuss a logic switching IDT first. - Move irq_vectors.h in the directory of arch/x86/include/asm/trace because I'm not sure if a logic switching IDT is sharable with other architectures. v3 - v4 - Add a latency measurement of each tracepoint - Rebased to 3.6-rc6 v2 - v3 - Remove an invalidate_tlb_vector event because it was replaced by a call function vector in a following commit. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit; h=52aec3308db85f4e9f5c8b9f5dc4fbd0138c6fa4 v1 - v2 - Modify variable name from irq to vector. - Merge arch-specific tracepoints below to an arch_irq_vector_entry/exit. - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector [Purpose of this patch] As Vaibhav explained in the thread below, tracepoints for irq vectors are useful. http://www.spinics.net/lists/mm-commits/msg85707.html snip The current interrupt traces from irq_handler_entry and irq_handler_exit provide when an interrupt is handled. They provide good data about when the system has switched to kernel space and how it affects the currently running processes. There are some IRQ vectors which trigger the system into kernel space, which are not handled in generic IRQ handlers. Tracing such events gives us the information about IRQ interaction with other system events. The trace also tells where the system is spending its time. We want to know which cores are handling interrupts and how they are affecting other processes in the system. Also, the trace provides information about when the cores are idle and which interrupts are changing that state. snip On the other hand, my usecase is tracing just local timer event and getting a value of instruction pointer. I suggested to add an argument local timer event to get instruction pointer before. But there is another way to get it with external module like systemtap. So, I don't need to add any argument to irq vector tracepoints now. [Patch Description] Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events. But there is an above use case to trace specific irq_vector rather than tracing all events. In this case, we are concerned about overhead due to unwanted events. This patch adds following tracepoints instead of introducing irq_vector_entry/exit. so that we can enable them independently. - local_timer_vector - reschedule_vector - call_function_vector - call_function_single_vector - irq_work_entry_vector - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector Also, it introduces a logic switching IDT at enabling/disabling time so that a time penalty makes a complete zero when tracepoints are disabled. Detailed explanations are as follows. - Create new irq handlers inserted tracepoints by using macros. - Create a new IDT, trace_idt_table, at boot time by duplicating original IDT, idt table, and registering the new handers for tracpoints. - Switch IDT to new one at enabling TP time. - Restore to an original IDT at disabling TP time. The new IDT is created only when CONFIG_TRACEPOINTS is enabled to avoid being used for other purposes. Signed-off-by: Seiji Aguchi seiji.agu...@hds.com --- arch/x86/include/asm/desc.h | 27 + arch/x86/include/asm/entry_arch.h| 32 + arch/x86/include/asm/hw_irq.h| 14 +++ arch/x86/kernel/Makefile
