[PATCH] perfmon: add context switch hooks for x86
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From: stephane eranian on 7 May 2008 04:40 Hello, Here is a first perfmon patch. It provides the following: - minimal perfmon source tree layout with a topdir perfmon for generic code and the x86 arch specific subdir in arch/x86. - the x86 perfmon context switch hooks in switch_to() and related TIF flag for both 32 and 64 bits. - a new X86 compile option (CONFIG_PERFMON) to enable/disable perfmon - placeholders for the actual generic context switch in/out routines in perfmon_ctxsw.c The patch does not do anything useful for end-users. Its goal is to establish the code layout and put in place the x86 context switch hooks and reserve the corresponding TIF bits. Please review. Changelog: - minimal perfmon source tree layout with a topdir perfmon for generic code and the x86 arch specific subdir in arch/x86/perfmon. - the x86 perfmon context switch hooks in switch_to() and related TIF flag for both 32 and 64 bits. - a new X86 compile option (CONFIG_PERFMON) to enable/disable perfmon - placeholders for the actual generic context switch in/out routine in perfmon_ctxsw.c Signed-off-by: Stephane Eranian <eranian(a)gmail.com> --- Makefile | 2 - arch/x86/Kconfig | 2 + arch/x86/kernel/process_32.c | 7 +++ arch/x86/kernel/process_64.c | 7 +++ arch/x86/perfmon/Kconfig | 10 +++++ include/asm-x86/thread_info_32.h | 8 ++-- include/asm-x86/thread_info_64.h | 5 ++ include/linux/perfmon_kern.h | 54 ++++++++++++++++++++++++++++++ perfmon/Makefile | 5 ++ perfmon/perfmon_ctxsw.c | 69 +++++++++++++++++++++++++++++++++++++++ 10 files changed, 164 insertions(+), 5 deletions(-) diff --git a/Makefile b/Makefile index 4492984..2385826 100644 --- a/Makefile +++ b/Makefile @@ -607,7 +607,7 @@ export mod_strip_cmd ifeq ($(KBUILD_EXTMOD),) -core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ +core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ perfmon/ vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \ $(core-y) $(core-m) $(drivers-y) $(drivers-m) \ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index bbcafaa..b43ae0c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1312,6 +1312,8 @@ config COMPAT_VDSO If unsure, say Y. +source "arch/x86/perfmon/Kconfig" + endmenu config ARCH_ENABLE_MEMORY_HOTPLUG diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index f8476df..10856c4 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -37,6 +37,7 @@ #include <linux/tick.h> #include <linux/percpu.h> #include <linux/prctl.h> +#include <linux/perfmon_kern.h> #include <asm/uaccess.h> #include <asm/pgtable.h> @@ -486,6 +487,9 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, prev = &prev_p->thread; next = &next_p->thread; + if (test_tsk_thread_flag(prev_p, TIF_PERFMON_CTXSW)) + pfm_ctxsw_out(prev_p, next_p); + debugctl = prev->debugctlmsr; if (next->ds_area_msr != prev->ds_area_msr) { /* we clear debugctl to make sure DS @@ -498,6 +502,9 @@ __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, if (next->debugctlmsr != debugctl) update_debugctlmsr(next->debugctlmsr); + if (test_tsk_thread_flag(next_p, TIF_PERFMON_CTXSW)) + pfm_ctxsw_in(prev_p, next_p); + if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { set_debugreg(next->debugreg0, 0); set_debugreg(next->debugreg1, 1); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index e2319f3..ee7eaff 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -37,6 +37,7 @@ #include <linux/kdebug.h> #include <linux/tick.h> #include <linux/prctl.h> +#include <linux/perfmon_kern.h> #include <asm/uaccess.h> #include <asm/pgtable.h> @@ -496,6 +497,9 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, prev = &prev_p->thread, next = &next_p->thread; + if (test_tsk_thread_flag(prev_p, TIF_PERFMON_CTXSW)) + pfm_ctxsw_out(prev_p, next_p); + debugctl = prev->debugctlmsr; if (next->ds_area_msr != prev->ds_area_msr) { /* we clear debugctl to make sure DS @@ -508,6 +512,9 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, if (next->debugctlmsr != debugctl) update_debugctlmsr(next->debugctlmsr); + if (test_tsk_thread_flag(next_p, TIF_PERFMON_CTXSW)) + pfm_ctxsw_in(prev_p, next_p); + if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { loaddebug(next, 0); loaddebug(next, 1); diff --git a/arch/x86/perfmon/Kconfig b/arch/x86/perfmon/Kconfig new file mode 100644 index 0000000..4c4813c --- /dev/null +++ b/arch/x86/perfmon/Kconfig @@ -0,0 +1,10 @@ +menu "Hardware Performance Monitoring support" +config PERFMON + bool "Perfmon2 performance monitoring interface" + select X86_LOCAL_APIC + default n + help + Enables the perfmon2 interface to access the hardware + performance counters. See <http://perfmon2.sf.net/> for + more details. +endmenu diff --git a/include/asm-x86/thread_info_32.h b/include/asm-x86/thread_info_32.h index b633882..626e326 100644 --- a/include/asm-x86/thread_info_32.h +++ b/include/asm-x86/thread_info_32.h @@ -141,6 +141,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_DEBUGCTLMSR 22 /* uses thread_struct.debugctlmsr */ #define TIF_DS_AREA_MSR 23 /* uses thread_struct.ds_area_msr */ #define TIF_BTS_TRACE_TS 24 /* record scheduling event timestamps */ +#define TIF_PERFMON_CTXSW 25 /* perfmon needs ctxsw calls */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) @@ -159,6 +160,7 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_DEBUGCTLMSR (1 << TIF_DEBUGCTLMSR) #define _TIF_DS_AREA_MSR (1 << TIF_DS_AREA_MSR) #define _TIF_BTS_TRACE_TS (1 << TIF_BTS_TRACE_TS) +#define _TIF_PERFMON_CTXSW (1 << TIF_PERFMON_CTXSW) /* work to do on interrupt/exception return */ #define _TIF_WORK_MASK \ @@ -168,9 +170,9 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP) /* flags to check in __switch_to() */ -#define _TIF_WORK_CTXSW \ - (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUGCTLMSR | \ - _TIF_DS_AREA_MSR | _TIF_BTS_TRACE_TS) +#define _TIF_WORK_CTXSW \ + (_TIF_IO_BITMAP | _TIF_NOTSC | _TIF_DEBUGCTLMSR | \ + _TIF_DS_AREA_MSR | _TIF_BTS_TRACE_TS | _TIF_PERFMON_CTXSW) #define _TIF_WORK_CTXSW_PREV _TIF_WORK_CTXSW #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW | _TIF_DEBUG) diff --git a/include/asm-x86/thread_info_64.h b/include/asm-x86/thread_info_64.h index cb69f70..f0f50f6 100644 --- a/include/asm-x86/thread_info_64.h +++ b/include/asm-x86/thread_info_64.h @@ -124,6 +124,7 @@ static inline struct thread_info *stack_thread_info(void) #define TIF_DS_AREA_MSR 26 /* uses thread_struct.ds_area_msr */ #define TIF_BTS_TRACE_TS 27 /* record scheduling event timestamps */ #define TIF_NOTSC 28 /* TSC is not accessible in userland */ +#define TIF_PERFMON_CTXSW 29 /* perfmon needs ctxsw calls */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) @@ -145,6 +146,7 @@ static inline struct thread_info *stack_thread_info(void) #define _TIF_DS_AREA_MSR (1 << TIF_DS_AREA_MSR) #define _TIF_BTS_TRACE_TS (1 << TIF_BTS_TRACE_TS) #define _TIF_NOTSC (1 << TIF_NOTSC) +#define _TIF_PERFMON_CTXSW (1<<TIF_PERFMON_CTXSW) /* work to do on interrupt/exception return */ #define _TIF_WORK_MASK \ @@ -158,7 +160,8 @@ static inline struct thread_info *stack_thread_info(void) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ - (_TIF_IO_BITMAP|_TIF_DEBUGCTLMSR|_TIF_DS_AREA_MSR|_TIF_BTS_TRACE_TS|_TIF_NOTSC) + (_TIF_IO_BITMAP|_TIF_DEBUGCTLMSR|_TIF_DS_AREA_MSR|_TIF_BTS_TRACE_TS|\ + _TIF_NOTSC|_TIF_PERFMON_CTXSW) #define _TIF_WORK_CTXSW_PREV _TIF_WORK_CTXSW #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW|_TIF_DEBUG) diff --git a/include/linux/perfmon_kern.h b/include/linux/perfmon_kern.h new file mode 100644 index 0000000..c7a8ace --- /dev/null +++ b/include/linux/perfmon_kern.h @@ -0,0 +1,54 @@ +/* + * Copyright (c) 2001-2006 Hewlett-Packard Development Company, L.P. + * Contributed by Stephane Eranian <eranian(a)gmail.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + * 02111-1307 USA + */ + +#ifndef __LINUX_PERFMON_KERN_H__ +#define __LINUX_PERFMON_KERN_H__ +/* + * This file contains all the definitions of data structures, variables, macros + * that are to be shared between generic code and arch-specific code + * + * For generic only definitions, use perfmon/perfmon_priv.h + */ +#ifdef __KERNEL__ + +#include <linux/sched.h> + +#ifdef CONFIG_PERFMON + + +void pfm_ctxsw_in(struct task_struct *prev, struct task_struct *next); +void pfm_ctxsw_out(struct task_struct *prev, struct task_struct *next); + +#else /* !CONFIG_PERFMON */ + +/* + * perfmon hooks are nops when CONFIG_PERFMON is undefined + */ +static inline void pfm_ctxsw_in(struct task_struct *prev, + struct task_struct *next) +{} + +static inline void pfm_ctxsw_out(struct task_struct *prev, + struct task_struct *next) +{} + +#endif /* CONFIG_PERFMON */ + +#endif /* __KERNEL__*/ +#endif /* __LINUX_PERFMON_KERN_H__ */ diff --git a/perfmon/Makefile b/perfmon/Makefile new file mode 100644 index 0000000..48563bd --- /dev/null +++ b/perfmon/Makefile @@ -0,0 +1,5 @@ +# +# Copyright (c) 2005-2006 Hewlett-Packard Development Company, L.P. +# Contributed by Stephane Eranian <eranian(a)gmail.com> +# +obj-$(CONFIG_PERFMON) = perfmon_ctxsw.o diff --git a/perfmon/perfmon_ctxsw.c b/perfmon/perfmon_ctxsw.c new file mode 100644 index 0000000..8399da7 --- /dev/null +++ b/perfmon/perfmon_ctxsw.c @@ -0,0 +1,69 @@ +/* + * perfmon_cxtsw.c: perfmon2 context switch code + * + * This file implements the perfmon2 interface which + * provides access to the hardware performance counters + * of the host processor. + * + * The initial version of perfmon.c was written by + * Ganesh Venkitachalam, IBM Corp. + * + * Then it was modified for perfmon-1.x by Stephane Eranian and + * David Mosberger, Hewlett Packard Co. + * + * Version Perfmon-2.x is a complete rewrite of perfmon-1.x + * by Stephane Eranian, Hewlett Packard Co. + * + * Copyright (c) 1999-2006 Hewlett-Packard Development Company, L.P. + * Contributed by Stephane Eranian <eranian(a)gmail.com> + * David Mosberger-Tang <davidm(a)hpl.hp.com> + * + * More information about perfmon available at: + * http://perfmon2.sf.net + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + * 02111-1307 USA + */ +#include <linux/kernel.h> +#include <linux/perfmon_kern.h> + +/** + * pfm_ctxsw_out - save PMU state on context switch out + * @prev: thread being switched out + * @next: thread being switched in + * + * We pass the next thread as on some platforms it may be necessary to + * pass some settings from the current thread to the next + * + * Interrupts are masked + */ +void pfm_ctxsw_out(struct task_struct *prev, + struct task_struct *next) +{ +} + +/** + * pfm_ctxsw_in - restore PMU state on context switch in + * @prev: thread being switched out + * @next: thread being switched in + * + * We pass the prev thread as on some platforms it may be necessary to + * pass some settings from the current thread to the next + * + * Interrupts are masked + */ +void pfm_ctxsw_in(struct task_struct *prev, + struct task_struct *next) +{ +} -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |