linux-kernel - Re: [PATCH 1/1] perf: Remove 'core

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Date:	Sun, 13 Mar 2016 19:54:19 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>, kan.liang@...el.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] perf: Remove 'core_id' check in topo test

On Thu, Dec 03, 2015 at 03:32:19PM -0800, Sukadev Bhattiprolu wrote:
> From b6bb5d9182f89cd7c6f1eff3cd5a6d3f947b8b0c Mon Sep 17 00:00:00 2001
> From: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
> Date: Thu, 3 Dec 2015 18:26:40 -0500
> Subject: [PATCH 1/1] perf: Remove 'core_id' check in topo test

hi,
looks like this one fell through the cracks

Arnaldo, could you please queue it..

Acked-by: Jiri Olsa <jolsa@...nel.org> ;-)

thanks,
jirka


> 
> The topology test case of 'perf test' seems to be broken on my x86
> system - due to the comparison of a "core-id" with # of CPUs online.
> 
> There are 8 online CPUs:
> 
> 	$ cat /sys/devices/system/cpu/online
> 	0-7
> 
> but core-ids are not sequential and some core-ids exceed the number
> of online CPUs.
> 
> 	$ cat /sys/devices/system/cpu/cpu?/topology/core_id
> 	0
> 	1
> 	9
> 	10
> 	0
> 	1
> 	9
> 	10
> 
> Looks like we can safely remove the check.  Output before:
> 
> 	$ ./perf --version
> 	perf version 4.4.rc1.g34258a
> 
> 	$ ./perf test -v topo
> 	36: Test topology in session                                 :
> 	--- start ---
> 	test child forked, pid 5906
> 	templ file: /tmp/perf-test-vCwWG3
> 	core_id number is too big.You may need to upgrade the perf tool.
> 	test child interrupted
> 	---- end ----
> 	Test topology in session: FAILED!
> 
> and after:
> 
> 	./perf test -v topo
> 	36: Test topology in session                                 :
> 	--- start ---
> 	test child forked, pid 6532
> 	templ file: /tmp/perf-test-y10wFJ
> 	CPU 0, core 0, socket 0
> 	CPU 1, core 1, socket 0
> 	CPU 2, core 9, socket 0
> 	CPU 3, core 10, socket 0
> 	CPU 4, core 0, socket 1
> 	CPU 5, core 1, socket 1
> 	CPU 6, core 9, socket 1
> 	CPU 7, core 10, socket 1
> 	test child finished with 0
> 	---- end ----
> 	Test topology in session: Ok
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
> Cc: kan.liang@...el.com
> Cc: Jiri Olsa <jolsa@...hat.com>
> ---
>  tools/perf/util/header.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 4383800..e74f94d 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1652,11 +1652,6 @@ static int process_cpu_topology(struct perf_file_section *section,
>  		if (ph->needs_swap)
>  			nr = bswap_32(nr);
>  
> -		if (nr > (u32)cpu_nr) {
> -			pr_debug("core_id number is too big."
> -				 "You may need to upgrade the perf tool.\n");
> -			goto free_cpu;
> -		}
>  		ph->env.cpu[i].core_id = nr;
>  
>  		ret = readn(fd, &nr, sizeof(nr));
> -- 
> 2.1.0
>