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

Eric Dumazet
2008-11-05T06:09:54Z

Eric Dumazet a écrit :
> Pekka J Enberg a écrit :
>> Hi Robert,
>>
>> On Tue, 4 Nov 2008, Robert Richter wrote:
>>> your patchset breaks oprofile on Intel Core 2 cpus. I could bisect the
>>> bug for c493756..5951290. Please take a look at this and send me a fix.
>>
>> Unfortunately I don't have my machine with me right now so I can't
>> test this, but don't we want something like this? Andi?
>
> Thanks a lot Pekka, this patch restores oprofile on my HP BL460c G1
>
> Tested-by: Eric Dumazet <dada1@cosmosbay.com>

Update :

After a while, no more NMI are delivered. No anymore samples.

# grep NMI /proc/interrupts
NMI: 214337 2004224 183702 2121878 641711 793553 18841 306364 Non-maskable interrupts
# grep NMI /proc/interrupts
NMI: 214337 2004224 183702 2121878 641711 793553 18841 306364 Non-maskable interrupts
# grep NMI /proc/interrupts
NMI: 214337 2004224 183702 2121878 641711 793553 18841 306364 Non-maskable interrupts
[root@svivoipvnx001 /opt/src/linux-2.6]$

# ps aux|grep oprof
root 5336 0.4 0.0 3512 1704 ? S 07:02 0:01 /usr/local/bin/oprofiled --session-dir=/var/lib/oprofile --separate-lib=0 --separate-kernel=0 --separate-thread=0 --separate-cpu=0 --events=CPU_CLK_UNHALTED:60:0:10000:0:1:1, --vmlinux=vmlinux --kernel-range=c02000a0,c045e9c1

# opcontrol --stop
Stopping profiling.
# opcontrol --start
Profiler running.
# grep NMI /proc/interrupts
NMI: 214337 2004224 183702 2121878 641711 793553 18841 306364 Non-maskable interrupts
# grep NMI /proc/interrupts
NMI: 214337 2004224 183702 2121878 641711 793553 18841 306364 Non-maskable interrupts

>
>>
>> Pekka
>>
>>> From 37d362c0262006be6a5d6a72b5993834afa776d7 Mon Sep 17 00:00:00 2001
>> From: Pekka Enberg <penberg@cs.helsinki.fi>
>> Date: Tue, 4 Nov 2008 21:17:47 +0200
>> Subject: [PATCH] oprofile: make perfmon nethalem only
>>
>> Commit b99170288421c79f0c2efa8b33e26e65f4bb7fb8 ("oprofile: Implement
>> Intel
>> architectural perfmon support") added perfmon support to newer Intel CPUs
>> (Core1+). The problem there is that it requires a patched oprofile
>> userland to
>> work properly.
>>
>> Fix that up by making oprofile perfmon support nethalem only.
>>
>> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
>> ---
>> arch/x86/oprofile/nmi_int.c | 7 +++++++
>> arch/x86/oprofile/op_model_ppro.c | 4 +++-
>> 2 files changed, 10 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
>> index 022cd41..1f4448e 100644
>> --- a/arch/x86/oprofile/nmi_int.c
>> +++ b/arch/x86/oprofile/nmi_int.c
>> @@ -426,8 +426,15 @@ static int __init ppro_init(char **cpu_type)
>>
>> static int __init arch_perfmon_init(char **cpu_type)
>> {
>> + __u8 cpu_model = boot_cpu_data.x86_model;
>> +
>> if (!cpu_has_arch_perfmon)
>> return 0;
>> +
>> + /* Nethalem only */
>> + if (cpu_model != 26)
>> + return 0;
>> +
>> *cpu_type = "i386/arch_perfmon";
>> model = &op_arch_perfmon_spec;
>> arch_perfmon_setup_counters();
>> diff --git a/arch/x86/oprofile/op_model_ppro.c
>> b/arch/x86/oprofile/op_model_ppro.c
>> index 0620d6d..1c91ba2 100644
>> --- a/arch/x86/oprofile/op_model_ppro.c
>> +++ b/arch/x86/oprofile/op_model_ppro.c
>> @@ -66,6 +66,7 @@ static void ppro_fill_in_addresses(struct op_msrs *
>> const msrs)
>>
>> static void ppro_setup_ctrs(struct op_msrs const * const msrs)
>> {
>> + __u8 cpu_model = boot_cpu_data.x86_model;
>> unsigned int low, high;
>> int i;
>>
>> @@ -76,7 +77,8 @@ static void ppro_setup_ctrs(struct op_msrs const *
>> const msrs)
>> return;
>> }
>>
>> - if (cpu_has_arch_perfmon) {
>> + /* Nethalem only */
>> + if (cpu_has_arch_perfmon && cpu_model == 26) {
>> union cpuid10_eax eax;
>> eax.full = cpuid_eax(0xa);
>> if (counter_width < eax.split.bit_width)
>
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