Lower-end optimization pass

[RunitaiLinden]

Test plan:

• Test on an machine with an Intel HD 4000, 4400, or Iris Xe video card
• Test on Nvidia GT 1030 if available
• Test on a laptop that has an AMD video card if available.
• Test on a Mac with a M1, M2, or M3 chip

1. Go to http://maps.secondlife.com/secondlife/Bug%20Island%202/107/14/23
2. Open the Texture Console. (Enable Preferences > Advanced > Show Develop Menu, then enable Develop > Consoles > Texture Console.)
3. To make the texture console easier to read, take a copy of the black object on the ground and attach it. It will attach to the HUD.
4. Look at the gray walls of textures to the South of you with the goal of loading as many as possible and causing the "Sys Free" number to fall below 512 in the texture console.
5. If "Sys Free" falls below 512, verify there is a log message in SecondLife.log, "Low system memory detected, emergency downrezzing off screen textures"
6. Verify Bias goes to 2.0 and Sys Free should immediately go up to around 500 MB.
7. Verify the framerate is smooth through all this without any noticable stalls or freezes.

Description

Profile and optimize viewer on laptop with Intel Iris Xe and 8GB of ram.

[canny[bot]]

This issue has been linked to a Canny post: PBR Performance Hit :tada:

[Dan-Linden]

Reopened to go through QA.

[DmitrySProductengine]

Passed QA. Verified on the Second Life Release 7.1.10.10582490681 (64bit) on Win10/Win11/OSX in the scope of IQA #316. Behavior according to the test plan - when Sys Free decreased less than 512 MB - Bias increased above 2 and then decreased to 1 when Sys Free increased more than 512 MB. Sys Free was always more than 512 MB on more modern computers with more RAM. We described such results in the following list. For some video cards, it was necessary to increase the graphics settings from the default ones - since on the default ones they also did not reduce the Sys Free below 512 MB

Tested on:

1. Intel: a) Intel HD Graphics 610 Screenshot Logs SecondLife_intel.log

b) Intel Iris XE: Win11, Graphics Card: Intel(R) Iris(R) Xe Graphics - Sys Free didn't fall below ~5200 in the texture console

2. Nvidia: a) Nvidia 730 Screenshot Logs SecondLife_nvidia 730.log

b) Nvidia 1050Ti Screenshot Logs SecondLife_nvidia 1050ti.log

3. AMD: a) HD 2600 XT Screenshot Logs SecondLife_radeon2600XT.log

b) AMD Radeon(TM) Graphics Win11, Graphics Card: AMD Radeon(TM) Graphics - Sys Free didn't fall below ~5400 in the texture console Screenshot

4. Mac with M2: a) Apple M2 (2400 MHz) Memory: 8192 MB Graphics Card: Apple M2 - Sys Free didn't fall below ~ 1100 in the texture console