linux-kernel - [Ping][PATCH] perf list: Add IBM z17 event descriptions

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Message-ID: <283e109b-9eb5-4e7d-b7df-215f54496503@linux.ibm.com>
Date: Fri, 27 Jun 2025 10:13:37 +0200
From: Thomas Richter <tmricht@...ux.ibm.com>
To: Ian Rogers <irogers@...gle.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-perf-users@...r.kernel.org, acme@...nel.org, namhyung@...nel.org,
        agordeev@...ux.ibm.com, gor@...ux.ibm.com, hca@...ux.ibm.com,
        japo@...ux.ibm.com
Subject: [Ping][PATCH] perf list: Add IBM z17 event descriptions

On 6/24/25 08:35, Thomas Richter wrote:

Gently Ping

Ian, I have responded to your comments some days ago.
See below.

Thanks a lot.

> On 6/23/25 19:53, Ian Rogers wrote:
>> On Mon, Jun 23, 2025 at 6:35 AM Thomas Richter <tmricht@...ux.ibm.com> wrote:
>>>
>>> Update IBM z17 counter description using document SA23-2260-08:
>>> "The Load-Program-Parameter and the CPU-Measurement Facilities"
>>> released in May 2025 to include counter definitions for IBM z17
>>> counter sets:
>>> * Basic counter set
>>> * Problem/user counter set
>>> * Crypto counter set.
>>>
>>> Use document SA23-2261-09:
>>> "The CPU-Measurement Facility Extended Counters Definition
>>>  for z10, z196/z114, zEC12/zBC12, z13/z13s, z14, z15, z16 and z17"
>>> released on April 2025 to include counter definitions for IBM z17
>>> * Extended counter set
>>> * MT-Diagnostic counter set.
>>>
>>> Use document SA22-7832-14:
>>> "z/Architecture Principles of Operation."
>>> released in April 2025 to include counter definitions for IBM z17
>>> * PAI-Crypto counter set
>>> * PAI-Extention counter set.
>>>
>>> Use document
>>> "CPU MF Formulas and Updates April 2025"
>>> released in April 2025 to include metric calculations.
>>>
>>> Signed-off-by: Thomas Richter <tmricht@...ux.ibm.com>
>>> Acked-by: Sumanth Korikkar <sumanthk@...ux.ibm.com>
>>
>> [snip]
>>
>>> +       {
>>> +               "Unit": "CPU-M-CF",
>>> +               "EventCode": "143",
>>> +               "EventName": "L1C_TLB2_MISSES",
>>> +               "BriefDescription": "L1C TLB2 Misses",
>>> +               "PublicDescription": "Increments by one for any cycle where a Level-1 cache or Level-2 TLB miss is in progress."
>>> +       },
>>
>> [snip]
>>
>>> +  {
>>> +    "BriefDescription": "Cycles per Instructions from Finite cache/memory",
>>> +    "MetricName": "finite_cpi",
>>> +    "MetricExpr": "L1C_TLB2_MISSES / INSTRUCTIONS if has_event(L1C_TLB2_MISSES) else 0"
>>> +  },
>>> +  {
>>> +    "BriefDescription": "Estimated Instruction Complexity CPI infinite Level 1",
>>> +    "MetricName": "est_cpi",
>>> +    "MetricExpr": "(CPU_CYCLES / INSTRUCTIONS) - (L1C_TLB2_MISSES / INSTRUCTIONS) if has_event(INSTRUCTIONS) else 0"
>>> +  },
>>> +  {
>>> +    "BriefDescription": "Estimated Sourcing Cycles per Level 1 Miss",
>>> +    "MetricName": "scpl1m",
>>> +    "MetricExpr": "L1C_TLB2_MISSES / (L1I_DIR_WRITES + L1D_DIR_WRITES) if has_event(L1C_TLB2_MISSES) else 0"
>>> +  },
>>
>> Just a quick check. If the PMU CPU-M-CF is always present then the
>> "has_event(L1C_TLB2_MISSES)" check will always be true as the event is
>> in json and not in sysfs. I'm guessing this is being done for the
>> benefit of hypervisors.
>>
> 
> The issue is indeed with z/VM, where the CPU Measurement facility is not exported to
> any guest OS including linux.
> If you run Linux on top of z/VM then these events do not exist.
> 
> # uname -a
> Linux a8345022.lnxne.boe 6.16.0-rc1m-perf #14 SMP Tue Jun 10 07:39:06 CEST 2025 s390x GNU/Linux
> # grep VM /proc/sysinfo 
> VM00 Name:            A8345022
> VM00 Control Program: z/VM    7.4.0   
> VM00 Adjustment:      50
> VM00 CPUs Total:      4
> VM00 CPUs Configured: 4
> VM00 CPUs Standby:    0
> VM00 CPUs Reserved:   0
> # lscpumf 
> lscpumf: No CPU-measurement facilities detected
> # 
> 
> Without this if..else the perf stat -e metric fail when Linux is installed on top of z/VM systems.
> See commit c2f3d7dfc7373 ("perf stat: Do not fail on metrics on s390 z/VM systems")
> 
> which fixed it for z16 machine generation.
> 
> Hope this helps.
> 
>> Thanks,
>> Ian
> 
> 

-- 
Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany
--
IBM Deutschland Research & Development GmbH

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