linux-kernel - [PATCH v4] perf/x86/intel/uncore: Fix CAS_COUNT

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Date:   Thu, 23 Dec 2021 22:48:26 +0800
From:   zhengjun.xing@...ux.intel.com
To:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     adrian.hunter@...el.com, alexander.shishkin@...el.com,
        ak@...ux.intel.com, kan.liang@...ux.intel.com,
        zhengjun.xing@...ux.intel.com, stable@...r.kernel.org
Subject: [PATCH v4] perf/x86/intel/uncore: Fix CAS_COUNT_WRITE issue for ICX

From: Zhengjun Xing <zhengjun.xing@...ux.intel.com>

The user recently report a perf issue in the ICX platform, when test by
perf event “uncore_imc_x/cas_count_write”,the write bandwidth is always
very small (only 0.38MB/s), it is caused by the wrong "umask" for the
"cas_count_write" event. When double-checking, find "cas_count_read"
also is wrong.

The public document for ICX uncore:

3rd Gen Intel® Xeon® Processor Scalable Family, Codename Ice Lake,Uncore
Performance Monitoring Reference Manual, Revision 1.00, May 2021

On 2.4.7, it defines Unit Masks for CAS_COUNT:
RD b00001111
WR b00110000

So corrected both "cas_count_read" and "cas_count_write" for ICX.

Old settings:
 hswep_uncore_imc_events
	INTEL_UNCORE_EVENT_DESC(cas_count_read,  "event=0x04,umask=0x03")
 	INTEL_UNCORE_EVENT_DESC(cas_count_write, "event=0x04,umask=0x0c")

New settings:
 snr_uncore_imc_events
	INTEL_UNCORE_EVENT_DESC(cas_count_read,  "event=0x04,umask=0x0f")
	INTEL_UNCORE_EVENT_DESC(cas_count_write, "event=0x04,umask=0x30")

Fixes: 2b3b76b5ec67 ("perf/x86/intel/uncore: Add Ice Lake server uncore support")
Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>
Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
Signed-off-by: Zhengjun Xing <zhengjun.xing@...ux.intel.com>
Cc: stable@...r.kernel.org
---
Change log:
  
  v4:
    * update commit log as Kan's suggestion

  v3:
    * Add change log

  v2:
    * Add stable tag

 arch/x86/events/intel/uncore_snbep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index 3660f698fb2a..ed869443efb2 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -5482,7 +5482,7 @@ static struct intel_uncore_type icx_uncore_imc = {
 	.fixed_ctr_bits	= 48,
 	.fixed_ctr	= SNR_IMC_MMIO_PMON_FIXED_CTR,
 	.fixed_ctl	= SNR_IMC_MMIO_PMON_FIXED_CTL,
-	.event_descs	= hswep_uncore_imc_events,
+	.event_descs	= snr_uncore_imc_events,
 	.perf_ctr	= SNR_IMC_MMIO_PMON_CTR0,
 	.event_ctl	= SNR_IMC_MMIO_PMON_CTL0,
 	.event_mask	= SNBEP_PMON_RAW_EVENT_MASK,
-- 
2.25.1