HOME / THE STATISTICS BAR

WHAT IS THE STATISTICS BAR?

The Statistics bar presents an detailed list of information about the performance of your computer and the Second Life world. While the sheer amount of information can be confusing, knowing what to look for can tell you a lot about what's going on in Second Life.

HOW DO I VIEW THE STATISTICS BAR?

You activate the Statistics bar with Ctrl+Shift+1 or by choosing Statistics Bar from your View menu.

WHAT DOES ALL THIS STUFF MEAN?

We'll go through each section in detail.

BASIC:

Displays basic information about your Second Life performance

FPS : The number of times per second your computer is redrawing (or refreshing) what's on the screen. Higher numbers are better. A frame rate between 15-30 frames per second (FPS) is about as smooth as broadcast television.

Bandwidth : How much data is being transferred between your computer and the Second Life world. This number varies wildly depending on what bandwidth settings you've used, where you are in-world, what's going on, and whether you're still loading some things (objects/textures/etc) that are in your field of view. If bandwidth is 0kbps, something may be wrong (you may be partially disconnected).

Packet Loss : The amount of data being lost as it travels between your computer and the server. Any nonzero packet loss is bad; packet loss above 10% is very bad. Packet loss might be caused by a dying server (in which case everyone in the region would be experiencing it), a bad connection between you and Second Life (possibly a bad router between your ISP and Second Life, or congestion at your ISP), or problems on your local network (wireless networking, or internet security or firewall software on your computer).

Ping Sim : How long it takes data to go from your computer to the region you're currently in. This is largely dependent on your connection to the Internet. If Ping Sim is high but Ping User is not, the server might be having problems.

Ping User : How long it takes data to go from Second Life to you. If Ping User is high, your connection might be having problems. (Your ISP might be congested, or your local network traffic might be blocked by a router or internet security/firewall software.)

ADVANCED

Displays lots of nitty-gritty details about your Second Life performance. Most of these details are less useful than Basic or Region.

Render : Displays information related to drawing the Second Life world.

KTris Drawn: (per frame) Computer-generated 3D objects are built out of triangles (the basic geometric shape). This is a count of the number of triangles, or "tris", in each frame of the current scene.

KTris Drawn: (per second) This is a count of the number of triangles ("tris") drawn every second.

Total Objs: The number of objects currently in view.

New Objs: The number of objects being created or destroyed.

Pipeline: Detailed information on the rendering process.
Visible Drawables:
Visible Faces:
DirtyGeom:
DirtyLight:
MoveList:
Compiles:
Verts Relit:

Texture: Detailed information on the textures currently in use.
Count :
GL Mem :
Formatted Mem :
Raw Mem :
Bound Mem :

REGION

Displays statistics for the region you're currently in.

OVERVIEW:

There was a major redesign in how the region operates in the 1.7 release. In previous releases, the region would run as quickly as it could, and then only run physics at a 45 frames per second. This meant that the region would run at very high frame rates (in the thousands) when there was no load, which was not a very efficient mode of operation. In addition, when there was a lot of scripts or many people connected to the region, the frame rate would drop and fluctuate as many scripts attempted to run on every frame.

In the following discussion an "agent" is either a user inside of a given region region (a "main agent") or a user in a neighboring region region (a "child agent"). Any user who can see objects inside a region region increases the load on that region.

Starting with release 1.7, the region scheduler was redesigned so that it attempts to run at a fixed frame rate which is the same as the physics frame rate. Instead of the region frame rate changing as load changes, the region will spend more or less time running LSL scripts each frame. This means that if there are a large number of scripts on the region, the frame rate will stay the same, but all of the scripts will run less frequently. Only in situations of particularly heavy physics load or large numbers of agents will the region frame rate drop from 45 frames/second.

In addition, there has been a major redesign of the logic which is used to transmit objects from the region to the viewers (called the interest list). The resulting improvements reduce the amount of load incurred when there are many agents on the same region.

The combination of the above two changes should result in significantly decreased "lag", and improved performance when many agents are on a region.

Reading the numbers
Because of the changes to the region execution model, most of the statistics which were used to evaluate region performance have been changed. Below is a detailed summary of what the current region performance statistics mean.

All of the numbers below are for regions running on a single region per CPU. On regions which are not running in this fashion (water regions, etc), these number will be different.

The following are the different statistics in the Region section of the statistics pane..

  • Time Dilation - The physics simulation rate relative to real-time. 1.0 means that the region is running at full speed, 0.5 means that physics is running at half-speed.
  • Sim FPS - The region frame rate. This should always be the same as the physics frame rate - 45.0 when things are running well.
  • Physics FPS - The frame rate that the physics engine is running at. This should normally be at or near 45.0.
  • Agent Updates/Sec - The rate at which agents on this region are being updated. Normally 20 updates a second, this will decrease if the region has a large number of agents on it.
  • Main Agents - The number of agents (users) who are on this region.
  • Child Agents - The number of agents who are not on this region, but can see it.
  • Objects - The total number of objects/primitives on the region
  • Active Objects - The number of moving and/or changing objects on the region.
  • Active Scripts - The number of running scripts that are currently on the region, including scripts attached to agents.
  • Script Perf - Number of LSL opcodes being executed a second by the region. Note that this is the number of ACTUAL instructions executed in the last second, not the theoretical maximum opcodes/second. If your region is not running very many scripts, this number will be low even if performance is good.
  • Packets In - UDP packets being received by the region
  • Packets Out - UDP packets being sent by the region
  • Pending Downloads - Number of asset downloads to the region that are pending. If this is greater than 1, this means that you may see delays in viewing notecards or scripts, and rezzing objects.
  • Pending Uploads - Number of current uploads of asset data pending. If this number is non-zero, this means that there may be performance issues when attempting to teleport.

The following are the different times listed in the Region/Time(ms) submenu of the statistics pane:

  • Total Frame Time - This measures how much time it takes the region to run everything that the region is trying to do each frame.
    • < 22 ms - the region is healthy, everything is running as fast as it can, and more scripts can be added without reducing the performance of individual scripts.
    • approx. 22 ms - the region is healthy, but there are probably a lot of scripts and agents on the region, meaning that script execution is being slowed down in order to maintain the region frame rate.
    • > 22 ms - the region is experiencing severe load, either due to physics or a large number of agents, such that even by slowing down script execution it is impossible to compensate. The region frame rate has been reduced as a result.
  • Net Time - The amount of time spent responding to incoming network data.
  • Sim Time (Physics) - The amount of time that frame spent running physics simulation. In general, this should be less than 5 milliseconds.
  • Sim Time (Other) - The amount of time that frame spent running other simulation (agent movement, weather simulation, etc.)
  • Agent Time - The amount of time spent updating and transmitting object data to the agents.
  • Images Time - The amount of time spent updating and transmitting image data to the agents.
  • Script Time - The amount of time spent running scripts.