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SubjectRe: [PATCH] [alpha] Add minimal support for software performance events.
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On Mon, Oct 26, 2009 at 3:32 AM, Michael Cree <mcree@orcon.net.nz> wrote:
> In the kernel the patch enables configuration of the perf event
> option, adds the perf_event_open syscall, and includes a minimal
> architecture specific asm/perf_event.h header file.
>
> For the perf tool the patch implements an Alpha specific section
> in the perf.h header file and adjusts options used in the
> Makefile to allow compilation on Alpha.  The -Wcast-align gives
> a "cast increases required alignment of target type" warning for
> the list_for_each_entry() macro. The -fstack-protector-all
> option generates a "not supported for this target" warning which
> with -Werror causes the compiler to abort.
>
> Signed-off-by: Michael Cree <mcree@orcon.net.nz>
> ---
>  arch/alpha/Kconfig                  |    1 +
>  arch/alpha/include/asm/perf_event.h |    9 +++++++++
>  arch/alpha/include/asm/unistd.h     |    3 ++-
>  arch/alpha/kernel/systbls.S         |    1 +
>  tools/perf/Makefile                 |    5 ++---
>  tools/perf/perf.h                   |    6 ++++++
>  6 files changed, 21 insertions(+), 4 deletions(-)
>  create mode 100644 arch/alpha/include/asm/perf_event.h
>
> diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
> index 4434481..bd7261e 100644
> --- a/arch/alpha/Kconfig
> +++ b/arch/alpha/Kconfig
> @@ -9,6 +9,7 @@ config ALPHA
>        select HAVE_IDE
>        select HAVE_OPROFILE
>        select HAVE_SYSCALL_WRAPPERS
> +       select HAVE_PERF_EVENTS
>        help
>          The Alpha is a 64-bit general-purpose processor designed and
>          marketed by the Digital Equipment Corporation of blessed memory,
> diff --git a/arch/alpha/include/asm/perf_event.h b/arch/alpha/include/asm/perf_event.h
> new file mode 100644
> index 0000000..3bef852
> --- /dev/null
> +++ b/arch/alpha/include/asm/perf_event.h
> @@ -0,0 +1,9 @@
> +#ifndef __ASM_ALPHA_PERF_EVENT_H
> +#define __ASM_ALPHA_PERF_EVENT_H
> +
> +/* Alpha only supports software events through this interface. */
> +static inline void set_perf_event_pending(void) { }
> +
> +#define PERF_EVENT_INDEX_OFFSET 0
> +
> +#endif /* __ASM_ALPHA_PERF_EVENT_H */
> diff --git a/arch/alpha/include/asm/unistd.h b/arch/alpha/include/asm/unistd.h
> index 17f72b7..414de17 100644
> --- a/arch/alpha/include/asm/unistd.h
> +++ b/arch/alpha/include/asm/unistd.h
> @@ -447,10 +447,11 @@
>  #define __NR_preadv                    489
>  #define __NR_pwritev                   490
>  #define __NR_rt_tgsigqueueinfo         491
> +#define __NR_perf_event_open           492
>
>  #ifdef __KERNEL__
>
> -#define NR_SYSCALLS                    492
> +#define NR_SYSCALLS                    493
>
>  #define __ARCH_WANT_IPC_PARSE_VERSION
>  #define __ARCH_WANT_OLD_READDIR
> diff --git a/arch/alpha/kernel/systbls.S b/arch/alpha/kernel/systbls.S
> index 78199b9..63c78e4 100644
> --- a/arch/alpha/kernel/systbls.S
> +++ b/arch/alpha/kernel/systbls.S
> @@ -510,6 +510,7 @@ sys_call_table:
>        .quad sys_preadv
>        .quad sys_pwritev                       /* 490 */
>        .quad sys_rt_tgsigqueueinfo
> +       .quad sys_perf_event_open
>
>        .size sys_call_table, . - sys_call_table
>        .type sys_call_table, @object
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 742a32e..7940d66 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -177,8 +177,7 @@ endif
>  # Include saner warnings here, which can catch bugs:
>  #
>
> -EXTRA_WARNINGS := -Wcast-align
> -EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat
> +EXTRA_WARNINGS := -Wformat
>  EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat-security
>  EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat-y2k
>  EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wshadow
> @@ -201,7 +200,7 @@ EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wold-style-definition
>  EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wstrict-prototypes
>  EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wdeclaration-after-statement
>
> -CFLAGS = $(MBITS) -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6 -fstack-protector-all -D_FORTIFY_SOURCE=2 $(EXTRA_WARNINGS)
> +CFLAGS = $(MBITS) -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6 -D_FORTIFY_SOURCE=2 $(EXTRA_WARNINGS)
>  LDFLAGS = -lpthread -lrt -lelf -lm
>  ALL_CFLAGS = $(CFLAGS)
>  ALL_LDFLAGS = $(LDFLAGS)
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index 8cc4623..216bdb2 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -47,6 +47,12 @@
>  #define cpu_relax()    asm volatile("":::"memory")
>  #endif
>
> +#ifdef __alpha__
> +#include "../../arch/alpha/include/asm/unistd.h"
> +#define rmb()          asm volatile("mb" ::: "memory")
> +#define cpu_relax()    asm volatile("" ::: "memory")
> +#endif
> +
>  #include <time.h>
>  #include <unistd.h>
>  #include <sys/types.h>
> --
> 1.6.3.3
>
> --

Please take a look at the attached patch and let me know if it's what
you want pushed. I wasn't sure if the last hunk (the memory barriers)
needed to be included or had already been picked up.

Thanks,
Matt
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