Re: [PATCH] Perf-tool/MIPS: support cross compiling of tools/perf for MIPS

[Wu Zhangjin <wuzhangjin@gmail.com>]

On Wed, 2010-04-28 at 19:54 +0800, Deng-Cheng Zhu wrote:
> With the kernel facility of Linux performance counters, we want the user
> level tool tools/perf to be cross compiled for MIPS platform. To do this,
> we need to include unistd.h, add rmb() and cpu_relax() in perf.h.
> 

Just found local-compiling also need rmb().

BTW: for local-compiling in a debian linux on MIPS machines, we need to
copy linux-source-code/{tools/perf, include, lib} to the machine and
install libdw-dev and libelf-dev, so the basic procedure for making perf
work on a debian/MIPS:

0. prepare

For tools/perf

  copy the directory {tools/perf, include, lib} of linux
  $ apt-get install libdw-dev libelf-dev

For the kernel support

  apply deng-cheng's latest patch and ensure CONFIG_HW_PERF_EVENTS=y
  then boot into the new kernel.

1. compile tools/perf

$ ls
include lib tools
$ ls tools/
perf
$ cd tools/perf
$ make

2. usage

$ ./perf list

For a non-raw event

$ ./perf stat -e cycles ls -l

For a raw event

$ ./perf stat -e r120 ls -l

Regard,

> Your review comments are especially required for the definition of rmb():
> In perf.h, we need to have a proper rmb() for _all_ MIPS platforms. And
> we don't have CONFIG_* things for use in here. Looking at barrier.h,
> rmb() goes into barrier() and __sync() for CAVIUM OCTEON and other CPUs,
> respectively. What's more, __sync() has different versions as well.
> Referring to BARRIER() in dump_tlb.c, I propose the "common" definition
> for perf tool rmb() in this patch. Do you have any comments?
> 
> In addition, for testing the kernel part code I sent several days
> ago, I was using the "particular" rmb() version for 24K/34K/74K cores:
> 
> #define rmb()           asm volatile(                           \
>                                 ".set   push\n\t"               \
>                                 ".set   noreorder\n\t"          \
>                                 ".set   mips2\n\t"              \
>                                 "sync\n\t"                      \
>                                 ".set   pop"                    \
>                                 : /* no output */               \
>                                 : /* no input */                \
>                                 : "memory")
> 
> This is the definition of __sync() for CONFIG_CPU_HAS_SYNC.
> 
> 
> Thanks,
> 
> Deng-Cheng
> 
> Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
> ---
>  tools/perf/perf.h |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index 6fb379b..cd05284 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -69,6 +69,18 @@
>  #define cpu_relax()	asm volatile("":::"memory")
>  #endif
>  
> +#ifdef __mips__
> +#include "../../arch/mips/include/asm/unistd.h"
> +#define rmb()		asm volatile(					\
> +				".set	noreorder\n\t"			\
> +				"nop;nop;nop;nop;nop;nop;nop\n\t"	\
> +				".set	reorder"			\
> +				: /* no output */			\
> +				: /* no input */			\
> +				: "memory")
> +#define cpu_relax()	asm volatile("" ::: "memory")
> +#endif
> +
>  #include <time.h>
>  #include <unistd.h>
>  #include <sys/types.h>