Changes To The Statistics Bar: What do they mean?

[Perrie Juran]

 

A few months ago changes were made to the Statistics Bar but I have yet to see any discussion or explanation (though it is possible I may have missed them).

Both the WIKI and the Knowledge Base have not been updated to reflect the changes. (On as side note both contain outdated information.  And a downside to the KB is that you can't see the history when changes are made).

"Bandwidth" has been replaced with "UDP Data Recieved" and "Cache Hit Rate" and "Read Latency" have been added.

So what would be good numbers here?  Is Cache Read measuring from Main Memory or from The GPU Cache? 

Etc, etc, etc.

ETA to add a screen shot.  I could have sworn I had an image posted when I first started this.  Odd.

[SaraCarena]

Cache hit rate = % of objects or textures loaded from cache rather than downloaded. There can be hit rates for objects or textures depends on what viewer, higher is better.

Cache latency = time taken to read data from cache, lower = better. With a high cache hit rate this tends to be lower, double digits. With a low cache hit rate latency tends to be higher, can be in the 1000`s or 10,000`s.

It means your sl cache so wherever that`s stored, so hard drive in most cases.

UDP data recieved, I assume means just what it says, bandwidth used by udp data.

Seems that viewer developers can customise the stats bar quite a lot and I think from memory that firestorm shows bandwidth for textures too.

There`s also a bandwidth monitor in the texture console. With http textures enabled this shows bandwidth used by http, so last night with the http problems it was barely reading into double digits. When http is behaving itself I`ve seen that spike well over 1.6 mbps but normally it`s in the 100`s. I was looking at the texture console last night an am still kicking myself for not realising it was screaming "http problem, disable http textures". That would have cured the "grey out" that I was having last night.

If you disable http textures the the texture console bandwidth monitor changes. It shows udp bandwidth but I think there is still some http activity too so may be a mixture of both but not quite sure about that.

 Agree that the stats bar wiki could use an update and maybe explained in less techy way.

 

EDIT: That looks like the firestorm stats bar. Also think that the sampling rate for some statistics varies from viewer to viewer. the cache hit rate stat seems more dynamic to me in sl viewer than the one in catznip.

[Ohjiro Watanabe]

Weird the way that thoes two graphs for the cache are either all green or all grey regardless of the value reported.

[Nalates Urriah]

The Bandwidth item has been confusing for some time. I think the only change there is the label.

Max Bandwidth and the Bandwidth stat have always shown UDP data flow. It just wasn't clear to any that had been inititted into the mystries of the stats panel. Earlier in SL's life moare data was transmitted via the UDP protocol, which has no error recovery. In that time it was common to have to clear cache to solve problems from corrupted textures.

Now more of the data travels by the HTTP protocol with error correction. We have far fewer problems with the cache now. Also the UDP numbers have less importance. We may see them disappear from the viewer stats and Preferences.

The Lindens are planning to take another look at how the viewer cache works. Most viewer developers say it doesn't work well. But, the caching is apparently spread through the viewer code in such a way that is is hard to change. So, as I understand it now, changing caching will be no small project. 

So, I am not surprised the stat is a bit flaky. Expect it to improve with time.

[WolfBaginski Bearsfoot]

I think that's a bug, Firestorm at least. If the stats window is recorded as open when you start the viewer, you get that effect. I see it clear when you close and re-open the stats window.

[Perrie Juran]

---

WolfBaginski Bearsfoot wrote:

I think that's a bug, Firestorm at least. If the stats window is recorded as open when you start the viewer, you get that effect. I see it clear when you close and re-open the stats window.

---

My image was taken in the official viewer.

The bar has more of an appearance of being an on/off indicator.

When Cache is being accessed it is all green.  When it is not being accessed you see all grey.

[SaraCarena]

Ohhhh, I see you`ve clicked to show the colour bar. I just keep that closed it`s only the numbers that mean anything anyway.

[Whirly Fizzle]

Its a bug

BUG-7053 - Statistics floater - Object Cache Hit Rate, Cache Hit Rate and Cache Read latency graphs display incorrectly