linux-kernel - Re: [PATCH] perf test powerpc: Fix 'Object code reading' test

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Message-ID: <fbc36209-2629-d32e-729b-1dc76816b453@intel.com>
Date:   Thu, 31 Aug 2017 09:49:11 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>, acme@...nel.org
Cc:     peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, namhyung@...nel.org,
        jolsa@...nel.org, linux-kernel@...r.kernel.org, mpe@...erman.id.au
Subject: Re: [PATCH] perf test powerpc: Fix 'Object code reading' test

On 31/08/17 09:38, Ravi Bangoria wrote:
> 'Object code reading' test always fails on powerpc. Two reasons for
> the failure are:
> 
> 1. When elf section is too big (size beyond 'unsigned int' max value).
> objdump fails to disassemble from such section. This was fixed with
> commit 0f6329bd7fc ("binutils/objdump: Fix disassemble for huge elf
> sections") in binutils.
> 
> 2. When the sample is from hypervisor. Hypervisor symbols can not
> be resolved within guest and thus thread__find_addr_map() fails for
> such symbols. Fix this by ignoring hypervisor symbols in the test.
> 
> Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
> ---
>  tools/perf/tests/code-reading.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
> index 761c5a4..8702592 100644
> --- a/tools/perf/tests/code-reading.c
> +++ b/tools/perf/tests/code-reading.c
> @@ -237,6 +237,10 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
>  
>  	thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
>  	if (!al.map || !al.map->dso) {
> +		/* Hyprevisor addr can not be resolved. */

Hyprevisor -> Hypervisor

> +		if (cpumode == PERF_RECORD_MISC_HYPERVISOR)

You need a pr_debug() message here e.g.
pr_debug("Hypervisor address can not be resolved - skipping\n");


> +			return 0;
> +
>  		pr_debug("thread__find_addr_map failed\n");
>  		return -1;
>  	}
>