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Operating system and version
NAME=Fedora
VERSION="27 (Twenty Seven)"
ID=fedora
VERSION_ID=27
PRETTY_NAME="Fedora 27 (Twenty Seven)"
ANSI_COLOR="0;34"
CPE_NAME="cpe:/o:fedoraproject:fedora:27"
HOME_URL="https://fedoraproject.org/"
SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=27
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=27
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
Fedora release 27 (Twenty Seven)
Fedora release 27 (Twenty Seven)
cpe:/o:fedoraproject:fedora:27
Kernel version: 4.18.8-100.fc27.x86_64
Tool version
Intel(R) VTune(TM) Profiler 2020 (build 605129) Command Line Tool
Copyright (C) 2009-2019 Intel Corporation. All rights reserved.
Compiler version
gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-6)
Steps to reproduce the error
vtunes with memory-access collector is always showing LLC miss counts as zero. And also the persistent memory bound is 0% which is suspect considering the high number of parallel IO threads. I have tried changing the kernel(5.0, 5.3 on another system with similar CPUs), use driverless mode instead of event-based profiling, rebuilding vtune with different options per user vs system wife, allowing multiple runs to disallow multiplexing PMC counters. Nothing as worked so far and have always seen LLC counter to zero.
Following is the vtune log of a sample run demonstrating the problem. I would highly appreciate it if someone could throw some light on this issue. Thanks in advance
CPU Time: 75.415s Memory Bound: 48.7% of Pipeline Slots | The metric value is high. This may indicate that a significant fraction | of execution pipeline slots could be stalled due to demand memory load | and stores. Explore the metric breakdown by memory hierarchy, memory | bandwidth information, and correlation by memory objects. | L1 Bound: 17.8% of Clockticks | This metric shows how often machine was stalled without missing the | L1 data cache. The L1 cache typically has the shortest latency. | However, in certain cases like loads blocked on older stores, a load | might suffer a high latency even though it is being satisfied by the | L1. | L2 Bound: 0.2% of Clockticks L3 Bound: 0.3% of Clockticks DRAM Bound: 0.0% of Clockticks DRAM Bandwidth Bound: 0.0% of Elapsed Time Store Bound: 12.6% of Clockticks NUMA: % of Remote Accesses: 0.0% UPI Utilization Bound: 0.0% of Elapsed Time Persistent Memory Bound: 0.0% of Clockticks Persistent Memory Bandwidth Bound: 0.0% of Elapsed Time Loads: 87,025,610,690 Stores: 36,653,099,560 LLC Miss Count: 0 Local DRAM Access Count: 0 Remote DRAM Access Count: 0 Local Persistent Memory Access Count: 0 Remote Persistent Memory Access Count: 0 Remote Cache Access Count: 0 Average Latency (cycles): 48 Total Thread Count: 30 Paused Time: 0s Bandwidth Utilization Bandwidth Domain Platform Maximum Observed Maximum Average % of Elapsed Time with High BW Utilization(%) ---------------------------------------- ---------------- ---------------- ------- --------------------------------------------- DRAM, GB/sec 220 18.300 6.460 0.0% DRAM Single-Package, GB/sec 110 18.200 6.706 0.0% UPI Utilization Single-link, (%) 100 10.800 6.538 0.0% Persistent Memory, GB/sec 60 10.600 5.603 0.0% Persistent Memory Single-Package, GB/sec 30 10.600 5.207 0.0% Collection and Platform Info Application Command Line: mpirun "--cpu-set" "24-43" "-np" "20" "--wdir" "./writer" "--bind-to" "core" "--mca" "btl" "tcp,self" "../workflowwriters" "1" "67108864" "16" User Name: ranjan Operating System: 4.18.8-100.fc27.x86_64 NAME=Fedora VERSION="27 (Twenty Seven)" ID=fedora VERSION_ID=27 PRETTY_NAME="Fedora 27 (Twenty Seven)" ANSI_COLOR="0;34" CPE_NAME="cpe:/o:fedoraproject:fedora:27" HOME_URL="https://fedoraproject.org/" SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help" BUG_REPORT_URL="https://bugzilla.redhat.com/" REDHAT_BUGZILLA_PRODUCT="Fedora" REDHAT_BUGZILLA_PRODUCT_VERSION=27 REDHAT_SUPPORT_PRODUCT="Fedora" REDHAT_SUPPORT_PRODUCT_VERSION=27 PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy" Computer Name: aep03 Result Size: 55 MB Collection start time: 23:38:34 31/01/2020 UTC Collection stop time: 23:38:43 31/01/2020 UTC
Collector Type: Event-based sampling driver CPU Name: Intel(R) Xeon(R) Processor code named Cascadelake Frequency: 2.394 GHz Logical CPU Count: 96 Max DRAM Single-Package Bandwidth: 110.000 GB/s
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