Optimizations

[Carterpersall]

This will be where I keep track of the improvements to Winfetch I make in various pull requests

How I achieve my speed improvements:

• Assume anything CIM and WMI will be slow and avoid it like the devil
• Piping is slow, so avoid using it when possible (do $e.Name instead of $e | Select-Object Name)
• Use https://github.com/nohwnd/Profiler and import generated JSON files into https://www.speedscope.app/ or view results directly in PowerShell
  • Shows which functions take the longest, but not what operations within the function take the longest. That takes looking into the function yourself and heavily leveraging Measure-Command
• I downclock my laptop hard (1.06 GHz) to get more battery life out of it. But what ends up happening with PowerShell is that slow operations take a very long time to execute, making speed differences much more noticeable
• Use preexisting values wherever possible
• Google things a lot. Even if you think you know how to do something fast, there may be a faster or easier solution out there
• Always investigate using a .NET library instead of a PowerShell command or CIM/WMI call, but don't assume that it will be faster
• $null = operation > [void]operation > operation | Out-Null
• Always check if $var | ForEach-Object or $variable.foreach() is faster
• Check if using [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey() is faster than Get-ItemProperty.

Notes to self:

• Keep an eye on the speed improvement of creating a CIM Instance
  • Currently negligible or faster in both slow and fast systems using both all functions and my personal config

TODO:

• Improve the beginning of the script
  • Add more arguments
  • Perform checks for variables only used in some functions
    • Implementing for the initial CIM declaration leads to speed regression
      • Checks for config values need to be almost negligible to be worth it
  • Create more variables for commands used in multiple functions
  • More and faster environment checking
• Improve the functions
  • info_ps_pkgs
    • Optimize ps_pkgs #163
    • 6630 ms
    • Maybe manually scan all PS Package Locations
  • info_pkgs
    • Speed Up info_pkgs #161
    • 2400 ms
  • info_gpu
    • Speed Up info_gpu #155
    • 1640 ms → 40.16 ms
      • 42x faster (nice)
  • info_cpu_usage
    • New CPU Usage Retrieval and Process Counting Method #160
    • 1035ms → 27.18ms
      • 38x Faster
  • info_locale
    • Speed Up info_locale #154
    • 3251 ms → 12.43 ms
      • 262x Faster
  • info_weather
    • New Weather Retrieval Method #158
    • 433 ms
  • info_local_ip
    • Implement Faster IPv4 Address Retrieval Method #159
    • 1673ms → 313ms
      • 6.3x Faster
  • info_memory
    • Attempted to reverse engineer Get-CimInstance
      • Initially tried (([System.Management.ManagementObjectSearcher]::new(([System.Management.ObjectQuery]::new("SELECT TotalVisibleMemorySize,FreePhysicalMemory FROM Win32_OperatingSystem")))).Get())
        • ~10ms slower (30ms → 40ms)
      • Then tried $cimSession.GetInstance("root/cimv2","Win32_OperatingSystem").CimInstanceProperties
        • ~18ms slower (30ms → 48.6)
        • Slower because it isn't grabbing specific properties, instead it is grabbing all of them
        • I later found $cimSession.EnumerateInstances("root/cimv2","Win32_OperatingSystem") which does the same thing but at about half the speed
      • After diving into how Get-CimInstance worked, I made $cimSession.QueryInstances("root/cimv2","WQL","SELECT TotalVisibleMemorySize,FreePhysicalMemory FROM Win32_OperatingSystem")
        • ~10ms slower (30 → 40ms)
        • The weird thing with this one is that this should be almost exactly what Get-CimInstance uses, except that it uses CimSession.QueryInstancesAsync() instead
      • Using my new knowledge of how Get-CimInstance worked, I then attempted to optimize the execution of the command
        • First tried defining the flags -QueryDialect WQL -Namespace root/cimv2 in an attempt to prevent the function from needing to retrieve it
          • Ended up decreasing speed extremely slightly
        • Then tried replacing the flags -ClassName Win32_OperatingSystem -Property TotalVisibleMemorySize,FreePhysicalMemory with -Query "SELECT TotalVisibleMemorySize,FreePhysicalMemory FROM Win32_OperatingSystem" to prevent the code from generating the query
          • Caused a very slight speed increase (<1ms)
        • Then I got curious and checked what the speed is when I removed -CimSession $cimSession
          • Ended up saving ~1ms somehow
          • Might not show this speed gain in the script though, as the reuse of the CimSession might be what it's missing here
• Implement multithreading
  • Multithreading with Runspaces #150
• Look into incorrect resolution being reported
  • Fix Resolution Bug #156

Speed Improvement (Excluding Multithreading):
Before:

• 18650 ms
• profiler_0001.speedscope.zip
  • Extract and upload to https://www.speedscope.app/ to view

After (Subtracting Speed Gains):

• 11444 ms
  • 63% Faster w. everything enabled