Re: linux-2.6.28-rc2 regression : oprofile doesnt work anymore ?

[Eric Dumazet]

Andi Kleen a écrit :
> Can you please test this patch and see if it solves the problem?
>
> Thanks,
> -Andi
>
> ---
>
> oprofile: Fix p6 counter overflow check
>
> Fix the counter overflow check for CPUs with counter width > 32
>
> I had a similar change in a different patch that I didn't submit
> and I didn't notice the problem earlier because it was always
> tested together.
>
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Thanks Andi

Unfortunatly, there is still a freeze of NMIS after a while.

# grep NMI /proc/interrupts
NMI:     127869     439091     905577       6158     809531      54720    4402881    2411582   Non-maskable interrupts
# grep NMI /proc/interrupts
NMI:     294473     765839    1174243     282249    1190866     382543    4747495    2463270   Non-maskable interrupts
# grep NMI /proc/interrupts
NMI:     294473     899262    1174243     282249    1282407     515973    5139226    2463270   Non-maskable interrupts
# grep NMI /proc/interrupts
NMI:     294473     899262    1174243     282249    1282407     515973    5187081    2463270   Non-maskable interrupts
# grep NMI /proc/interrupts
NMI:     294473     899262    1174243     282249    1282407     515973    5187081    2463270   Non-maskable interrupts
# grep NMI /proc/interrupts
NMI:     294473     899262    1174243     282249    1282407     515973    5187081    2463270   Non-maskable interrupts
# grep NMI /proc/interrupts
NMI:     294473     899262    1174243     282249    1282407     515973    5187081    2463270   Non-maskable interrupts
#

# grep . /dev/oprofile/*/*
/dev/oprofile/0/count:10000
/dev/oprofile/0/enabled:1
/dev/oprofile/0/event:60
/dev/oprofile/0/kernel:1
/dev/oprofile/0/unit_mask:0
/dev/oprofile/0/user:1
/dev/oprofile/1/count:0
/dev/oprofile/1/enabled:0
/dev/oprofile/1/event:0
/dev/oprofile/1/kernel:0
/dev/oprofile/1/unit_mask:0
/dev/oprofile/1/user:0
/dev/oprofile/stats/bt_lost_no_mapping:0
/dev/oprofile/stats/event_lost_overflow:376941
/dev/oprofile/stats/sample_lost_no_mapping:43358
/dev/oprofile/stats/sample_lost_no_mm:26

# grep . /dev/oprofile/*
/dev/oprofile/backtrace_depth:0
grep: /dev/oprofile/buffer: Device or resource busy
/dev/oprofile/buffer_size:1048576
/dev/oprofile/buffer_watershed:32768
/dev/oprofile/cpu_buffer_size:65536
/dev/oprofile/cpu_type:i386/core_2
grep: /dev/oprofile/dump: Invalid argument
/dev/oprofile/enable:1
/dev/oprofile/pointer_size:4



> ---
>  arch/x86/oprofile/op_model_ppro.c |    9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> Index: linux-2.6.28-rc3-test/arch/x86/oprofile/op_model_ppro.c
> ===================================================================
> --- linux-2.6.28-rc3-test.orig/arch/x86/oprofile/op_model_ppro.c	2008-11-07 13:46:23.000000000 +0100
> +++ linux-2.6.28-rc3-test/arch/x86/oprofile/op_model_ppro.c	2008-11-07 13:50:57.000000000 +0100
> @@ -27,8 +27,7 @@
>  static int counter_width = 32;
>  
>  #define CTR_IS_RESERVED(msrs, c) (msrs->counters[(c)].addr ? 1 : 0)
> -#define CTR_READ(l, h, msrs, c) do {rdmsr(msrs->counters[(c)].addr, (l), (h)); } while (0)
> -#define CTR_OVERFLOWED(n) (!((n) & (1U<<(counter_width-1))))
> +#define CTR_OVERFLOWED(n) (!((n) & (1ULL<<(counter_width-1))))
>  
>  #define CTRL_IS_RESERVED(msrs, c) (msrs->controls[(c)].addr ? 1 : 0)
>  #define CTRL_READ(l, h, msrs, c) do {rdmsr((msrs->controls[(c)].addr), (l), (h)); } while (0)
> @@ -124,14 +123,14 @@
>  static int ppro_check_ctrs(struct pt_regs * const regs,
>  			   struct op_msrs const * const msrs)
>  {
> -	unsigned int low, high;
> +	u64 val;
>  	int i;
>  
>  	for (i = 0 ; i < num_counters; ++i) {
>  		if (!reset_value[i])
>  			continue;
> -		CTR_READ(low, high, msrs, i);
> -		if (CTR_OVERFLOWED(low)) {
> +		rdmsrl(msrs->counters[i].addr, val);
> +		if (CTR_OVERFLOWED(val)) {
>  			oprofile_add_sample(regs, i);
>  			wrmsrl(msrs->counters[i].addr, -reset_value[i]);
>  		}


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