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Violators will be prosecuted for from ; Fri, 24 Apr 2015 14:25:18 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id DF263125804F for ; Fri, 24 Apr 2015 14:27:14 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay04.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t3O8tEo166257134 for ; Fri, 24 Apr 2015 14:25:15 +0530 Received: from d28av01.in.ibm.com (localhost [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t3O8tEsp029987 for ; Fri, 24 Apr 2015 14:25:14 +0530 From: "Naveen N. Rao" To: linuxppc-dev@lists.ozlabs.org, rostedt@goodmis.org Subject: [PATCH v2] powerpc/ftrace: add powerpc timebase as a trace clock source Date: Fri, 24 Apr 2015 14:24:44 +0530 Message-Id: <1429865684-6214-1-git-send-email-naveen.n.rao@linux.vnet.ibm.com> Cc: paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Add a new powerpc-specific trace clock using the timebase register, similar to x86-tsc. This gives us - a fast, monotonic, hardware clock source for trace entries, and - a clock that can be used to correlate events across cpus as well as across hypervisor and guests. Signed-off-by: Naveen N. Rao --- Changes since v1: - removed unnecessary #ifdef in trace_clock.h - changed config build dependency for trace_clock.o from TRACE_CLOCK to TRACING Documentation/trace/ftrace.txt | 5 +++++ arch/powerpc/include/asm/Kbuild | 1 - arch/powerpc/include/asm/trace_clock.h | 19 +++++++++++++++++++ arch/powerpc/kernel/Makefile | 1 + arch/powerpc/kernel/trace_clock.c | 15 +++++++++++++++ 5 files changed, 40 insertions(+), 1 deletion(-) create mode 100644 arch/powerpc/include/asm/trace_clock.h create mode 100644 arch/powerpc/kernel/trace_clock.c diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index 572ca92..689f61a 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -346,6 +346,11 @@ of ftrace. Here is a list of some of the key files: x86-tsc: Architectures may define their own clocks. For example, x86 uses its own TSC cycle clock here. + ppc-tb: This uses the powerpc timebase register value. + This is in sync across CPUs and can also be used + to correlate events across hypervisor/guest if + tb_offset is known. + To set a clock, simply echo the clock name into this file. echo global > trace_clock diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild index 382b28e..5041c66 100644 --- a/arch/powerpc/include/asm/Kbuild +++ b/arch/powerpc/include/asm/Kbuild @@ -5,5 +5,4 @@ generic-y += mcs_spinlock.h generic-y += preempt.h generic-y += rwsem.h generic-y += scatterlist.h -generic-y += trace_clock.h generic-y += vtime.h diff --git a/arch/powerpc/include/asm/trace_clock.h b/arch/powerpc/include/asm/trace_clock.h new file mode 100644 index 0000000..cf1ee75 --- /dev/null +++ b/arch/powerpc/include/asm/trace_clock.h @@ -0,0 +1,19 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2, as + * published by the Free Software Foundation. + * + * Copyright (C) 2015 Naveen N. Rao, IBM Corporation + */ + +#ifndef _ASM_PPC_TRACE_CLOCK_H +#define _ASM_PPC_TRACE_CLOCK_H + +#include +#include + +extern u64 notrace trace_clock_ppc_tb(void); + +#define ARCH_TRACE_CLOCKS { trace_clock_ppc_tb, "ppc-tb", 0 }, + +#endif /* _ASM_PPC_TRACE_CLOCK_H */ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 502cf69..18e038e 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -118,6 +118,7 @@ obj-$(CONFIG_PPC_IO_WORKAROUNDS) += io-workarounds.o obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o +obj-$(CONFIG_TRACING) += trace_clock.o ifneq ($(CONFIG_PPC_INDIRECT_PIO),y) obj-y += iomap.o diff --git a/arch/powerpc/kernel/trace_clock.c b/arch/powerpc/kernel/trace_clock.c new file mode 100644 index 0000000..4917069 --- /dev/null +++ b/arch/powerpc/kernel/trace_clock.c @@ -0,0 +1,15 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2, as + * published by the Free Software Foundation. + * + * Copyright (C) 2015 Naveen N. Rao, IBM Corporation + */ + +#include +#include + +u64 notrace trace_clock_ppc_tb(void) +{ + return get_tb(); +} -- 2.3.5