Tuesday, October 12, 2021

Tuning Microsoft Windows for CPU Cryptocurrency Mining

This post covered setup and basic configuration of a Monero crypto miner on Microsoft Windows.

The PC had 16GB of RAM, and rarely used more than 9GB of RAM. In the Performance tab of Task Manager, under Memory, it shows the amount of RAM in use and the amount compressed. RAM compression uses a small (and typically unnoticeable amount of CPU to compress RAM pages which are not being used. While compressed RAM pages can't actually be used by a process when they are compressed, the idea is that by compressing RAM it may avoid swapping RAM to disk in a low-memory situation. Certainly reading swapped pages from disk should be considerably slower than  using CPU to uncompress RAM pages which are already in memory. For anyone using a machine which is not using all of the RAM, this is an optimization looking for a problem - if the machine is not swapping, then there is no RAM slowdown due to swapping. Compressing RAM when there is not a RAM shortage slightly increases CPU use. While the small additional CPU use may not be noticeable on many workloads, it can be noticeable and detrimental to do this speculative RAM optimization when the CPU is already near 100% usage, as is typical when mining a cryptocurrency on CPUs.


With the machine not in danger of swapping in-memory RAM pages to disk, let's turn off RAM compression. In the worst case if a process takes more RAM than the installed 16GB, some pages will be swapped to disk as has been standard for decades.

In this example with the Monero miner and a web browser and other applications, Task Manager shows the machine had 5.2GB available and 1.6GB compressed of 15.9GB total RAM. Even if the compressed RAM is uncompressed at triple the compressed size, everything should still fit into the real 15.9GB of RAM.


Let's look at the current RAM compression setting. Right-click on the Start Button and choose "Windows PowerShell (Admin)". Then in PowerShell run this command: Get-MMAgent

This shows "MemoryCompression" is set to True. This confirms what can be seen in the Task Manager, that some amount of the memory was "Compressed". Get some statistics with: Get-Process -Name "Memory Compression"

Disable RAM compression with: Disable-MMAgent -MemoryCompression

Reboot so the change will take effect. After reboot, use PowerShell to check that the setting is False with: Get-MMAgent

Run your typical processes, and also run the Monero crypto miner. Look at Task Manager. In this example, Task Manager shows about 7GB of RAM available without using compression. Note that "(Compressed)" is zero.


Presumably the Microsoft Windows 10 developers put considerable effort into optimizing the RAM compression code. When a machine is pushed to limits such as nearly 100% CPU, there may be noticeable performance differences when turning off the speculative RAM compression. In general use, we should expect to find the changes basically unnoticeable from a user interface standpoint. On CPU-bound processes like crypto mining we might be able to see a performance change. I was surprised to find a consistent increase in Monero mining performance (measured via hashes per second) of over 15%. The peak hash per second increased over 20%.

While this dramatic increase was unexpected, it shows the dangers of premature optimization ("let's do RAM compression just because it might be good"). It also shows the benefit of benchmarking before and after a change. Both before and after the change the "huge pages" mining feature was enabled.


October 17 update on Monero miner tuning - it makes a small difference by forcing the miner to avoid using CPU core 0. On the machine in this example, there are four CPU cores. The mining process consistently starts three processes, which leaves one of the cores unused. The unused core was consistently core 3, and cores 0 - 2 were consistently pegged at 100% CPU usage. On a hunch that hardware interrupts may still be serviced by core 0, I used Task Manager to set processor affinity to cores 1 - 3. This had the effect of moving the miner process off core 0.

Task Manager shows a process named "System interrupts". This is more of an indication of interrupts rather than a real process. If a hardware driver is misbehaving, this process could indicate greater than zero CPU usage. In a properly functioning system, interrupts should have nearly zero CPU usage. It is possible that even with low CPU usage, interrupts are causing miner code removal from the core along with possible small CPU cache issues.


The Performance Monitor application allowed viewing of percentage interrupt time. Right-click and choose "Add counters" then look for "Processor information" to find "% Interrupt Time". The first counter in the following graph is the overall interrupt counter and one counter for each of the four CPU cores. The scale on the graph is increased from 1 to 100 to highlight the differences. CPU core zero (colored red) frequently spikes. The overall interrupt (color blue) also spikes though is tempered by the other CPUs. The lines for CPUs 1 - 3 are flatlined against the bottom of the graph. This shows interrupts are being serviced by CPU 0. Therefore, removing the mining process from CPU 0 should provide smoother process execution as measured by better program throughput.


Looking at the hashes per second of the monero miner process, the high-water mark increased about 6% and a day the average hashes per second increased about 3%. On a mining process, a 3% increase in performance at no hardware cost is a nice improvement. A more precise performance measurement would need a dedicated machine running without other programs and measured for several days.

The following line has been added to the command file to set the processor affinity when the miner is started:
start /BELOWNORMAL /affinity E /b E:\tech\crypto\monero\GUIs\xmrig-6.15.1-msvc-win64\xmrig-6.15.1\xmrig.exe -o pool.supportxmr.com:443 -u 44YkNzrdJnmAqwoTRMPV2e4fihv3AfZ5vMmrtaWCGQaxKuXp5eiZeRREzhPi9tVqGuA3VBRriNwKa2QxmZmRGmHVTkUSTMc -k --tls -p runDemoA

While affinity "E" works for this four-core system, it depends on your CPU core count along with available hyper-threads so please view this post to determine the binary number. Then view this website to convert the binary number to hexadecimal to use with the "affinity" flag of the "start" command.

Affinity "E" will put threads on CPU cores 1 and 2 and 3, so use this for a process with three threads - using this with 1 or 2 threads will typically shift the CPU core over time, which can be seen in Task Manager cpu view. Affinity "A" would be two threads on CPU cores 1 and 3. Please verify the number of threads in the program, and match that to specific CPU cores by using the correct hexadecimal value which you can find in the prior links.


Tuning update for CPU hyper-threading:

Hyper-threading allows a CPU core to support, typically, two separate threads. The idea is that usually threads do not use the maximum available CPU on a core (not completely CPU bound) because program code often waits for network or disk or user interaction. During that time of waiting, the other thread can run on the CPU core. If the CPU core is already 100% consumed by a thread then adding another thread does not increase throughput.

BIOS settings can often turn off CPU hyper-threading, though this may not be available in some laptop BIOS. Using BIOS to turn off and on hyper-threading, the miner ran about 2.5% better with hyper-threading off. Throughput went from 826 hashes per second to 846 hashes per second. This was tested on two separate machines of the same make and model, with similar performance improvements on both machines.


This page has instructions on becoming a MS Windows user with Admin privilege to set the "lock pages" feature, which is also known as huge pages. To summarize, run the Local Security Policy editor, choose Local Policies, choose User Rights Assignment, choose Lock Pages In Memory, and double-click and add the user.





Sunday, October 10, 2021

How to mine Monero on Microsoft Windows

If you are interested in trying to try out mining a cryptocurrency, this guide can be used by most people - even those with low internet bandwidth and a weak or old computer. You will learn the mechanics of how to mine a cryptocurrency through a pool, though don't expect to make much money.

Bitcoin was the original cryptocurrency, with the proof of work software released in January 2009. Proof of work means the cryptocurrency mining software performs calculations using the CPU to determine which miner will put the next block of transactions onto the blockchain. The Bitcoin software can still be run on CPUs, though the majority of the miners use specialized hardware which is optimized to specifically run the Bitcoin mining algorithm. 

The other well-known mining algorithm is proof of stake. In general, this requires a person to "stake" tokens or coins as collateral. Based on shares or round-robin or other methodology, a staker is chosen to submit the next block of transactions. If an invalid block is submitted, others can slash the staked tokens as a penalty.

Ethereum is a proof of work cryptocurrency which is undergoing changes which will allow the network to move to proof of stake. Some people consider proof of stake to have advantages over proof of work, including using a small fraction of the electricity consumed by proof of work blockchains.

Monero is a proof of work blockchain which is specifically designed to be mined only on computer CPUs. This makes mining on video graphics cards or specialized hardware difficult and not cost effective. By allowing anyone to run the mining code on a CPU and to be competitive, Monero aims to create a larger and more distributed group of miners.


This post focuses on running Monero mining software on Microsoft Windows through a mining pool. The mining pool reduces network and storage costs by relieving the client machine from hosting the full node software to route and store transactions. While this allows a person to more easily mine, it does reduce the usefulness of the mining node to submit and validate transactions. Nonetheless, mining Monero through a pool is a good way to gain mining experience.


The basic tasks for running a Monero mining node is to download and install the software, create a wallet, and then run and monitor the mining code.

The cryptocurrency wallet creates and stores a private key / public key pair. The wallet can typically view balances and send and receive coins.

For now, let's focus on mining using Microsoft Windows, a wallet, and the xmrig software. Download the xmrig software from github. Look for the win64 version. Use Windows File Explorer to uncompress the zipped folder. Go into the folder structure (currently it looks like "xmrig-6.15.1-msvc-win64\xmrig-6.15.1"). Create a file named something like startminer.cmd as a txt file. This is a Windows Command Script file which will contain your settings and run the miner.

Edit startminer.cmd and add these three lines:
@echo off
xmrig.exe -o pool.supportxmr.com:443 -u 44YkNzrdJnmAqwoTRMPV2e4fihv3AfZ5vMmrtaWCGQaxKuXp5eiZeRREzhPi9tVqGuA3VBRriNwKa2QxmZmRGmHVTkUSTMc -k --tls -p runDemoA
pause

Open a command prompt by pressing Windows Start Button, type cmd, and click on the Command Prompt app. Go to the location of the startminer.cmd file. Type: startminer.cmd 
Depending on your internet filtering and DNS settings, you may see some warnings. Also, Microsoft Windows security may flag the miner as being a cryptocurrency miner trojan. Since you want to be mining, disable this specific security warning.

After the miner is running, you may use a web browser to monitor your miner. Please note the mining pool at SupportXMR receives at least a 1% fee for their services, and any mining rewards will go to the address in the command script which starts with "44...".

The Command Prompt window will continue to show output from the miner. In the following picture, the first two orange circles show that Microsoft Windows has "core isolation" memory integrity turned on and that it uses a Virtual Machine. If your operating system is running with the VM on (probably a good thing for most people), ignore these apparent errors in the first two orange circles. The third orange circle shows the current mining work output. This picture is from an older machine which shows how a CPU which is several years old can be used to mine transactions via a mining pool.

To monitor the miner in the mining pool, go to SupportXMR.com and enter the public key from the Command Script file: 44YkNzrdJnmAqwoTRMPV2e4fihv3AfZ5vMmrtaWCGQaxKuXp5eiZeRREzhPi9tVqGuA3VBRriNwKa2QxmZmRGmHVTkUSTMc

You will be able to see information including the custom name in the startminer.cmd file, along with your hash rate.


It is typically good to lower the operating system priority of the mining process to reduce interference with other processes on the machine. You certainly want to lower the priority if you are also using the machine for regular play and work. Right-click on the Windows Start Button and click on Task Manager. In task manager click on the Details tab. Click on the CPU column so the highest CPU consumer will appear at the top. This will typically be the xmrig.exe mining software. Right-click on the xmrig.exe line, and set the Priority to Below Normal.

Download the wallet software and install the program. Create a new wallet, and write down the recovery words. Learn more by reading the wallet README.


Copy the wallet primary account address and the public key from the GUI wallet. You can put that address into your Command Script file and restart the miner to allow any rewards to go to your wallet.



Saturday, October 09, 2021

Microsoft Windows File Explorer Customization

The File Explorer in Microsoft Windows allows access to various context-sensitive menus by right-clicking the mouse button. You may customize many of the menus. This post will show you how to modify the context-sensitive menus for "new" file, "open with", and "send to".

The "new" menu may already have items for BMP image and several other document types. Look at your configuration by going to an empty place on the Desktop or in File Explorer, right-click the mouse button, and go to New.


Let's add an item to create a new JPEG image. Press the Windows Start Button and type registry. Click on the Registry Editor app. 

In the Registry Editor go to registry key: HKEY_CLASSES_ROOT\.jpg

Right-click on ".jpg" and add a new Key with name ShellNew.

In ShellNew, create a new "String Value" with value of FileName. Modify the FileName entry with "Value Data" of Template.jpg.


You may close the Registry Editor. Now right-click on the Desktop or in File Explorer, go to New, and there should be an option to create a new JPEG image.



The context-sensitive Open With menu shows appropriate choices for each file type. Because there are many file types, there are many settings which may be shown depending on the file type. In the following picture, this is a text file and the file type is ".txt".



Create the new text document, then right-click on the file and go to the Open With entry. You should see various text editors.



These settings are stored in the Windows registry and may be modified with the Registry Editor for each file type.

Let's add a program in the Open With menu. Click on the Windows Start Button, type regedit, and click on Registry Editor.

In the left pane of the Registry Editor, go to key: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\

Go to the .txt entry, and click on OpenWithList.



Add the office writer application to the Open With menu for ".txt" files. In the right-hand panel, right-click and press New, String Value. The Value Name should be the next letter in the alphabet. 

Double-click the new entry and in the Value Data field add the office writer application of "soffice.exe".


Now when you go to the Open With item, you should see the office writer application as a choice.

While you are in Registry Editor, you may also remove items. Go to the file type, select the item, and then press Delete.



The Send To in File Explorer is a context-sensitive menu which appears when you right-click an item. Let's add an item to the list.


Press the Windows Start Button and type: run
Click the Run App. In the Run app, enter shell:sendto and press the OK button.



This will open a folder which contains the various items. 



Delete any items you do not want by selecting the item and deleting it. 


Add items by copying a shortcut to the program into this folder. For example, if you would like Microsoft Paint to appear in the Send To menu, find the path to the program (Start Button, scroll to Windows Accessories and expand it, right-click on Paint, choose More, then choose Open File Location. After the File Explorer window open, right-click on Paint and choose Copy. In the SendTo folder, right-click on a white sort and choose Paste Shortcut.)


The SendTo folder will look like:


Now when you are in File Explorer and right-click an item to display the context-sensitive menu, Send To will show the new entry which you just added. It may be useful to add the Notepad application to the Send To menu to make it easy to quickly bring up the editor for working with ".cmd" files (Windows command script files or batch files).