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Re: [PATCH]: Fix suboptimal mcount on sparc.


From: David Miller <davem@davemloft.net>
Date: Wed, 14 May 2008 03:33:38 -0700 (PDT)

Ping?

> The current use of the generic version results in a full stack frame
> being created for _mcount, and also a flush of the entire set of
> register windows just to grab the parent program counter.
> 
> This patch fixes all of those inefficiencies.
> 
> Fully regression tested on sparc*-linux and sparc64*-linux
> 
> Please apply, thanks.
> 
> 2008-05-14  David S. Miller  <davem@davemloft.net>
> 
> 	* sysdeps/sparc/machine-gmon.h: New file.
> 	* sysdeps/sparc/sparc-mcount.S: Likewise.
> 	* sysdeps/sparc/Makefile: Add sparc-mcount target to
> 	sysdep_routines in gmon directory.
> ---
>  sysdeps/sparc/Makefile       |    4 ++++
>  sysdeps/sparc/machine-gmon.h |   33 +++++++++++++++++++++++++++++++++
>  sysdeps/sparc/sparc-mcount.S |   29 +++++++++++++++++++++++++++++
>  3 files changed, 66 insertions(+), 0 deletions(-)
>  create mode 100644 sysdeps/sparc/machine-gmon.h
>  create mode 100644 sysdeps/sparc/sparc-mcount.S
> 
> diff --git a/sysdeps/sparc/Makefile b/sysdeps/sparc/Makefile
> index 40323a0..9fa5324 100644
> --- a/sysdeps/sparc/Makefile
> +++ b/sysdeps/sparc/Makefile
> @@ -1,6 +1,10 @@
>  # The Sparc `long double' is a distinct type we support.
>  long-double-fcts = yes
>  
> +ifeq ($(subdir),gmon)
> +sysdep_routines += sparc-mcount
> +endif
> +
>  ifeq ($(subdir),db2)
>  CPPFLAGS += -DHAVE_SPINLOCKS=1 -DHAVE_ASSEM_SPARC_GCC=1
>  endif
> diff --git a/sysdeps/sparc/machine-gmon.h b/sysdeps/sparc/machine-gmon.h
> new file mode 100644
> index 0000000..296c5ff
> --- /dev/null
> +++ b/sysdeps/sparc/machine-gmon.h
> @@ -0,0 +1,33 @@
> +/* sparc-specific implementation of profiling support.
> +   Copyright (C) 2008 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +   Contributed by David S. Miller <davem@davemloft.net>, 2008
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library 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
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, write to the Free
> +   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> +   02111-1307 USA.  */
> +
> +#include <sysdep.h>
> +
> +/* We must not pollute the global namespace.  */
> +#define mcount_internal __mcount_internal
> +
> +extern void mcount_internal (u_long frompc, u_long selfpc) internal_function;
> +
> +#define _MCOUNT_DECL(frompc, selfpc) \
> +void internal_function mcount_internal (u_long frompc, u_long selfpc)
> +
> +/* Define MCOUNT as empty since we have the implementation in another
> +   file.  */
> +#define MCOUNT
> diff --git a/sysdeps/sparc/sparc-mcount.S b/sysdeps/sparc/sparc-mcount.S
> new file mode 100644
> index 0000000..573b08f
> --- /dev/null
> +++ b/sysdeps/sparc/sparc-mcount.S
> @@ -0,0 +1,29 @@
> +/* sparc-specific implemetation of profiling support.
> +   Copyright (C) 2008 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +   Contributed by David S. Miller <davem@davemloft.net>, 2008.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library 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
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, write to the Free
> +   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> +   02111-1307 USA.  */
> +
> +#include <sysdep.h>
> +
> +ENTRY(_mcount)
> +	mov	%i7, %o0
> +	ba	__mcount_internal
> +	 mov	%o7, %o1
> +END(_mcount)
> +
> +weak_alias (_mcount, mcount)
> -- 
> 1.5.5.1.57.g5909c
> 


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