[kvm-unit-tests PATCH RESEND 1/2] x86/pmu: Make "ref cycles" test to pass on the latest cpu

[kvm-unit-tests PATCH RESEND 1/2] x86/pmu: Make "ref cycles" test to pass on the latest cpu

[Like Xu]

From: Like Xu <likexu@tencent.com>

Expand the boundary for "ref cycles" event test as it has
been observed that the results do not fit on some CPUs [1]:

FAIL: full-width writes: ref cycles-N
  100000 >= 87765 <= 30000000
  100000 >= 87926 <= 30000000
  100000 >= 87790 <= 30000000
  100000 >= 87687 <= 30000000
  100000 >= 87875 <= 30000000
  100000 >= 88043 <= 30000000
  100000 >= 88161 <= 30000000
  100000 >= 88052 <= 30000000

[1] Intel(R) Xeon(R) Platinum 8374C CPU @ 2.70GHz

Opportunistically fix cc1 warnings for commented print statement.

Signed-off-by: Like Xu <likexu@tencent.com>
---
 x86/pmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/x86/pmu.c b/x86/pmu.c
index 92206ad..3d05384 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -86,7 +86,7 @@ struct pmu_event {
 } gp_events[] = {
 	{"core cycles", 0x003c, 1*N, 50*N},
 	{"instructions", 0x00c0, 10*N, 10.2*N},
-	{"ref cycles", 0x013c, 0.1*N, 30*N},
+       {"ref cycles", 0x013c, 0.08*N, 30*N},
 	{"llc refference", 0x4f2e, 1, 2*N},
 	{"llc misses", 0x412e, 1, 1*N},
 	{"branches", 0x00c4, 1*N, 1.1*N},
@@ -223,7 +223,7 @@ static void measure(pmu_counter_t *evt, int count)
 
 static bool verify_event(uint64_t count, struct pmu_event *e)
 {
-	// printf("%lld >= %lld <= %lld\n", e->min, count, e->max);
+	// printf("%d >= %ld <= %d\n", e->min, count, e->max);
 	return count >= e->min  && count <= e->max;
 
 }
-- 
2.35.1

[kvm-unit-tests PATCH RESEND 2/2] x86/pmu: Fix a comment about full-width counter writes support

[Like Xu]

From: Like Xu <like.xu@linux.intel.com>

From: Like Xu <like.xu@linux.intel.com>

Remove two Unicode characters 'ZERO WIDTH SPACE' (U+200B).

Fixes: 22f2901a0e ("x86: pmu: Test full-width counter writes support")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
 x86/pmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/x86/pmu.c b/x86/pmu.c
index 3d05384..052c2b7 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -587,7 +587,7 @@ static void  check_gp_counters_write_width(void)
 	}
 
 	/*
-	 * MSR_IA32_PMCn supports writing values ​​up to GP counter width,
+        * MSR_IA32_PMCn supports writing values up to GP counter width,
 	 * and only the lowest bits of GP counter width are valid.
 	 */
 	for (i = 0; i < num_counters; i++) {
-- 
2.35.1

Re: [kvm-unit-tests PATCH RESEND 1/2] x86/pmu: Make "ref cycles" test to pass on the latest cpu

[Jim Mattson]

On Wed, Mar 2, 2022 at 3:26 AM Like Xu <like.xu.linux@gmail.com> wrote:
>
> From: Like Xu <likexu@tencent.com>
>
> Expand the boundary for "ref cycles" event test as it has
> been observed that the results do not fit on some CPUs [1]:
>
> FAIL: full-width writes: ref cycles-N
>   100000 >= 87765 <= 30000000
>   100000 >= 87926 <= 30000000
>   100000 >= 87790 <= 30000000
>   100000 >= 87687 <= 30000000
>   100000 >= 87875 <= 30000000
>   100000 >= 88043 <= 30000000
>   100000 >= 88161 <= 30000000
>   100000 >= 88052 <= 30000000
>
> [1] Intel(R) Xeon(R) Platinum 8374C CPU @ 2.70GHz
>
> Opportunistically fix cc1 warnings for commented print statement.
>
> Signed-off-by: Like Xu <likexu@tencent.com>

This fix doesn't address the root cause of the problem, which is that
the general purpose reference cycles event is, in many cases,
decoupled from CPI. My proposed fix,
https://lore.kernel.org/kvm/20220213082714.636061-1-jmattson@google.com/,
does.

Re: [kvm-unit-tests PATCH RESEND 2/2] x86/pmu: Fix a comment about full-width counter writes support

[Jim Mattson]

On Wed, Mar 2, 2022 at 3:26 AM Like Xu <like.xu.linux@gmail.com> wrote:
>
> From: Like Xu <like.xu@linux.intel.com>
>
> From: Like Xu <like.xu@linux.intel.com>
>
> Remove two Unicode characters 'ZERO WIDTH SPACE' (U+200B).
>
> Fixes: 22f2901a0e ("x86: pmu: Test full-width counter writes support")
> Reported-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Like Xu <like.xu@linux.intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

Re: [kvm-unit-tests PATCH RESEND 1/2] x86/pmu: Make "ref cycles" test to pass on the latest cpu

[Paolo Bonzini]

On 3/2/22 18:39, Jim Mattson wrote:
> On Wed, Mar 2, 2022 at 3:26 AM Like Xu <like.xu.linux@gmail.com> wrote:
>>
>> From: Like Xu <likexu@tencent.com>
>>
>> Expand the boundary for "ref cycles" event test as it has
>> been observed that the results do not fit on some CPUs [1]:
>>
>> FAIL: full-width writes: ref cycles-N
>>    100000 >= 87765 <= 30000000
>>    100000 >= 87926 <= 30000000
>>    100000 >= 87790 <= 30000000
>>    100000 >= 87687 <= 30000000
>>    100000 >= 87875 <= 30000000
>>    100000 >= 88043 <= 30000000
>>    100000 >= 88161 <= 30000000
>>    100000 >= 88052 <= 30000000
>>
>> [1] Intel(R) Xeon(R) Platinum 8374C CPU @ 2.70GHz
>>
>> Opportunistically fix cc1 warnings for commented print statement.
>>
>> Signed-off-by: Like Xu <likexu@tencent.com>
> 
> This fix doesn't address the root cause of the problem, which is that
> the general purpose reference cycles event is, in many cases,
> decoupled from CPI. My proposed fix,
> https://lore.kernel.org/kvm/20220213082714.636061-1-jmattson@google.com/,
> does.
> 

Queued yours, together with Like's patch 2.

Paolo