linux-kernel - Re: [patch 2/8] 2.6.22-rc3 perfmon2 : Debug messages added

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Date:	Wed, 20 Jun 2007 12:49:05 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Robert Richter <robert.richter@....com>
cc:	Stephane Eranian <eranian@....hp.com>,
	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org
Subject: Re: [patch 2/8] 2.6.22-rc3 perfmon2 : Debug messages added

On Wed, 20 Jun 2007, Robert Richter wrote:

> Debug messages added for better debugging.
> 

And you added BUG_ON()'s.

> Signed-off-by: Robert Richter <robert.richter@....com>
> 
> Index: linux-2.6.22-rc3/perfmon/perfmon_file.c
> ===================================================================
> --- linux-2.6.22-rc3.orig/perfmon/perfmon_file.c
> +++ linux-2.6.22-rc3/perfmon/perfmon_file.c
> @@ -192,6 +192,8 @@ static int pfm_mmap(struct file *file, s
>  	unsigned long flags;
>  	int ret;
>  
> +	PFM_DBG("pfm_file_ops");

After commenting on your first set of patches, I've been using it a little 
more.  In my use, these debugging messages weren't very helpful because 
"pfm_file_ops" can indicate pfm_mmap, pfm_read, pfm_poll, etc.  Could 
these be changed to be more specific based on the function they're in?

> Index: linux-2.6.22-rc3/perfmon/perfmon_syscalls.c
> ===================================================================
> --- linux-2.6.22-rc3.orig/perfmon/perfmon_syscalls.c
> +++ linux-2.6.22-rc3/perfmon/perfmon_syscalls.c
> @@ -403,6 +403,8 @@ asmlinkage long sys_pfm_create_context(s
>  	void *fmt_arg = NULL;
>  	int ret;
>  
> +	PFM_DBG("syscall");

Likewise.  Using "syscall" for all debugging messages in the syscall 
handlers isn't very informative.  Could this be PFM_DBG(__FUNCTION__) 
instead?

> +
>  	if (atomic_read(&perfmon_disabled))
>  		return -ENOSYS;
>  
> @@ -433,8 +435,12 @@ asmlinkage long sys_pfm_write_pmcs(int f
>  	size_t sz;
>  	int ret, fput_needed;
>  
> -	if (count < 0 || count >= PFM_MAX_ARG_COUNT(ureq))
> +	PFM_DBG("syscall");
> +
> +	if (count < 0 || count >= PFM_MAX_ARG_COUNT(ureq)) {
> +                PFM_DBG("invalid arg count %d", count);

This is whitespace damaged.

>  		return -EINVAL;
> +	}
>  
>  	sz = count*sizeof(*ureq);
>  
> @@ -475,6 +481,8 @@ asmlinkage long sys_pfm_write_pmcs(int f
>  		kfree(fptr);
>  error:
>  	fput_light(filp, fput_needed);
> +	if (ret)
> +		PFM_DBG("failed: errno=%d", -ret);

What failed?  More information would be helpful since this is, after all, 
a diagnostic message.

> Index: linux-2.6.22-rc3/include/asm-i386/perfmon.h
> ===================================================================
> --- linux-2.6.22-rc3.orig/include/asm-i386/perfmon.h
> +++ linux-2.6.22-rc3/include/asm-i386/perfmon.h
> @@ -140,6 +140,10 @@ static inline void pfm_arch_write_pmc(st
>  	if (ctx && ctx->flags.started == 0)
>  		return;
>  
> +	PFM_DBG_ovfl("pfm_arch_write_pmc(0x%016Lx, 0x%016Lx)",
> +		     (unsigned long long) pfm_pmu_conf->pmc_desc[cnum].hw_addr,
> +		     (unsigned long long) value);

Casting here should be unnecessary.  Changing %L would be advisible to 
display the data as it is stored in the object.

> +	BUG_ON(pfm_pmu_conf->pmc_desc[cnum].type & PFM_REG_V);
>  	if (arch_info->pmu_style == PFM_X86_PMU_P4)
>  		__pfm_write_reg_p4(&arch_info->pmc_addrs[cnum], value);
>  	else
> @@ -155,6 +159,10 @@ static inline void pfm_arch_write_pmd(st
>  	if (pfm_pmu_conf->pmd_desc[cnum].type & PFM_REG_C64)
>  		value |= ~pfm_pmu_conf->ovfl_mask;
>  
> +	PFM_DBG_ovfl("pfm_arch_write_pmd(0x%016Lx, 0x%016Lx)",
> +		     (unsigned long long) pfm_pmu_conf->pmd_desc[cnum].hw_addr,
> +		     (unsigned long long) value);
> +	BUG_ON(pfm_pmu_conf->pmd_desc[cnum].type & PFM_REG_V);
>  	if (arch_info->pmu_style == PFM_X86_PMU_P4)
>  		__pfm_write_reg_p4(&arch_info->pmd_addrs[cnum], value);
>  	else
> @@ -165,10 +173,14 @@ static inline u64 pfm_arch_read_pmd(stru
>  {
>  	struct pfm_arch_pmu_info *arch_info = pfm_pmu_conf->arch_info;
>  	u64 tmp;
> +	BUG_ON(pfm_pmu_conf->pmd_desc[cnum].type & PFM_REG_V);
>  	if (arch_info->pmu_style == PFM_X86_PMU_P4)
>  		__pfm_read_reg_p4(&arch_info->pmd_addrs[cnum], &tmp);
>  	else
>  		rdmsrl(pfm_pmu_conf->pmd_desc[cnum].hw_addr, tmp);
> +	PFM_DBG_ovfl("pfm_arch_read_pmd(0x%016Lx) = 0x%016Lx",
> +		     (unsigned long long) pfm_pmu_conf->pmd_desc[cnum].hw_addr,
> +		     (unsigned long long) tmp);
>  	return tmp;
>  }
>  
> @@ -176,10 +188,14 @@ static inline u64 pfm_arch_read_pmc(stru
>  {
>  	struct pfm_arch_pmu_info *arch_info = pfm_pmu_conf->arch_info;
>  	u64 tmp;
> +	BUG_ON(pfm_pmu_conf->pmc_desc[cnum].type & PFM_REG_V);
>  	if (arch_info->pmu_style == PFM_X86_PMU_P4)
>  		__pfm_read_reg_p4(&arch_info->pmc_addrs[cnum], &tmp);
>  	else
>  		rdmsrl(pfm_pmu_conf->pmc_desc[cnum].hw_addr, tmp);
> +        PFM_DBG_ovfl("pfm_arch_read_pmc(0x%016Lx) = 0x%016Lx",
> +		     (unsigned long long) pfm_pmu_conf->pmc_desc[cnum].hw_addr,
> +		     (unsigned long long) tmp);

More whitespace damage.
-
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