2024 HPC-AI Winter Camp @ NTHU & NCHC

Brief Introduction to Intel® VTune™ Profilers

Clone this repo:

git clone https://github.com/nevikw39/HPC-Winter-Camp-Profiling

Please be advised that, in the code blocks of this document, you should replace the variables start with $ (like $RESULT_DIR) on your own.

Before We Start

For APS and VTune™, we need either X11 forwarding or copying data back.

SSH X11 Forwarding

Allow you to open GUI application running remotely on local computer.

Prerequiste:

• Linux: Noting to do if X11 desktop has been installed
• macOS: Xquatrz is required
• Windows: Enable WSLg with WSL 2, or use other X11 server like VcXsrv, Xming or one within MobaXTerm

Then, before establishing SSH connection, add -X -Y options or set ForwardX11Trusted yes, ForwardX11 yes in your SSH config.

ssh -X -Y $USER@clogin1.twnia.nchc.org.tw
# Use another login node
ssh -X -Y $USER@clogin2.twnia.nchc.org.tw

To check whether that works, you could open some X11 apps:

xclock
xcalc
xlogo
xeyes

SSH Key for Data Transfer Nodes

In addition to login nodes or computation nodes, Taiwania 1 has data transfer nodes (xdata1, xdata2) dedicated to uploading or downloading files or directories through SSH or SFTP.

Thankfully, we are able to login to these data transfer nodes with SSH key only!!

If you don't have a pair of SSH key, you could generate one now:

ssh-keygen

Then, store it to ~/.ssh/authorized_keys on the machine you would like to login to.

Set up Environments on Taiwania 1

Remember that there are 2 login nodes, clogin1 (clogin1.twnia.nchc.org.tw or 140.110.148.11) and clogin2 (clogin2.twnia.nchc.org.tw or 140.110.148.12)!!

# Load Intel Compiler
module load intel/2019_u5 
# ``Source'' VTune
. /pkg/intel/2019_u5/vtune_amplifier/amplxe-vars.sh
# Select locale
export LC_CTYPE=en_US

Intel® VTune™ Amplifier’s Application Performance Snapshot

Generate Results

APS would first create a directory containing results. By default, the directory would be named after date and time. It could be specified through --result-dir=$RESULT_DIR optionally.

aps $APPLICATION $APPLICATION_PARAMETERS
# or
aps --result-dir=$RESULT_DIR $APPLICATION $APPLICATION_PARAMETERS

Convert Result to Report

Then, we need obtain the analysis report (in HTML) based on the result data. By default, the report would also be named after date and time. It could be specified via -O $REPORT_FILE optionally.

aps-report $RESULT_DIR
# or
aps-report $RESULT_DIR -O $REPORT_FILE

Study the Report

There are 3 ways to view the report:

X11 Forwarding

If you have had X11 Forwarding set properly, you could start web browsers like FireFox:

firefox $REPORT_FILE

Copy Report Back to Local

Otherwise, you could download the HTML back to your own computer and open it. That could be done by VSCode, MobaXTerm or scp:

scp $USER@xdata1.twnia.nchc.org.tw:$PATH_TO_REPORT_FILE .

Note that if you upload your public SSH key to Taiwania 1, you could transfer data with xdata1, xdata2 nodes without OTP!!

Launch Simple Server and Port Forwarding

Alternatively, you might launch a simple web server (like python -m SimpleHTTPServer or python3 -m http.server) on Taiwania 1. Nevertheless, there exists firewall blocking some traffic. So we should forward port with SSH. Choose a randome port or you would collide with others!!

Intel® VTune™ Amplifier

Note that in newer version, amplxe-cl & amplxe-gui would be vtune & vtune-gui, respectively.

Collect Data

Common available collect options:

• Hotspots (hotspots)
• Memory Consumption (memory-consumption)
• Microarchitecture Exploration (uarch-exploration)
• Memory Access (memory-access)
• Threading (threading)
• HPC Performance Characterization (hpc-performance)
• I/O (io)

amplxe-cl -collect $COLLECT_OPTION -r $RESULT_DIR $APPLICATION $APPLICATION_PARAMETERS

View the Report

Similarly, there are also 3 approaches to open the reports.

X11 Forwarding

Again, if X11 Forwarding have been set properly, we could start the GUI:

amplxe-gui $RESULT_DIR

Install VTune™ Locally & Copy Report Back to Local

Otherwise, you could install VTune™ on your own computer and then download the HTML back. Downloading could be done by VSCode, MobaXTerm or scp:

# Note the `-r` option and the `/' at the end of the path!!
scp -r $USER@xdata1.twnia.nchc.org.tw:$PATH_TO_RESULT_DIR/ .
# Use another data transfer node
scp -r $USER@xdata2.twnia.nchc.org.tw:$PATH_TO_RESULT_DIR/ .

Note that if you upload your public SSH key to Taiwania 1, you could transfer data with xdata1, xdata2 nodes without OTP!!

Launch Backend and Port Forwarding

Alternatively, Intel® provides VTune™ backend (amplxe-backend or vtune-backend) which works just like a web server. We could lauch it on Taiwania 1. Again, due to the firewall, we should forward port with SSH.