some data on SL data usage.

[Rhys Goode]

I read with interest the recent threads about execss data use and possible server bugs.  I was on the road two weeks ago, and had to use my wireless 4-G USB modem to run SL.  And I had noticed, that I was using nearly 1 GB/session, where in the past I had only been using about 400 or 500 Meg. (Typically 2 or 3 hours of SL in a "session")  Since I have a monthly limit of 5 GB on the data plan, I decided I need to understand things a bit better.

So, I set about making some measurements. I have a network monitor that tracks the amount of data downloaded to my computer. It has about 5 minutes worth of scrolling history of data rate, and a stopwatch.  For my measuements, I could settle down in place, and wait till I reached a nice stable data rate, then use the stopwatch. Randomly TP'ing around, I found lots of places with a nice flat graph of data rate vs time, and lots of places that were quite "noisey", with lots of data spikes. Eventually, I figured out that some of those spikes were AV's TPing into the region. And that different music streams have different signatures, mostly very spikey, sending data in bursts every 0.1 to a few secs, depending on the stream. The monitor measures data in bits (and kilo bits and mega bits), so I had to convert to Bytes.  To make sure I was getting it right, I looked at a couple of 128 kbps music streams, which calculate out to 0.055 GB/hr. I measured 0.057 GB/h, close enough for government work.

For my measurements I turned the music and media off.  My goal here to understand how to manage *my* data use, not to understand the mysteries of SL.  I used the default graphics settings for "high". Each time I moved, I waited for a stable data rate, and did not change my camera during a set of measurement.  Changing the view always creates a transient increase in the data rate.

I hang out in my own house. And I have a platform, currently empty, 3000 m above it.  And I have a friend with an isolated shop on a 512^m skybox in a different sim.  I went to each, waited for the data rate to stabilize, then started adjusting the draw distance. I rather suspected that I would see data rate smoothly increase with draw distance, at least for my living room, on the ground in a mainland sim.  Neither my own skybox, nor my friends shop, have anything as closer than about 500 m, so I expected them to be very dull.

Well, I was wrong. Home was nice and low, ~0.02 GB/hr, up to a draw distance of about 175. Then it abruptly jumped to about 0.12, a factor of 6 jump!  .Increasing the draw distance over 250 m, there is another abrupt jump, up to about 0.3 GB/hr (alarmingly high on a 5 GB per month budget). These are abrubt, reproduceable steps. On the plot, the points at 96, 200, and 300 were taken twice, after tuning up and down in draw distance several times

The empty sky box, over my home? Very low data rate, ~ 0.01 GB/hr, but only for small draw distance.  There is an abrupt jump, up to around 0.10 GB/hr, similar to the one seen in my living room, but at a lower draw distance.

My friend's shop also has a big, abrupt step in data rate at higher draw distance. The shop is relatively consistant for small draw ditances, about 0.05 GB/hr.  This is quite a bit higher than for low draw distances in my living room, but then there is a lot of stuff in the shop. The abrupt step at around 275 m is even worse here. From .05 up to over 0.3, another factor of six for a small change in settings.

I spend a fair amount of time in clubs. So I looked at 3 of them. Two were in active use, one was completely empty. The empty sim had about the lowest data rate I saw, less than 0.01 GB/hr And it showed only a moderate bump in data rate, even when the draw distance reached the shops, about 150 m away. The two active clubs, surprised me. I really expected to see much higher data rates than for my home or an empty shop. It was harder to take data, there were a lot more transient events, avatars coming and going. One of the clubs was fairly level out the 300 m, the other had a big jump  in data rate for draw distance ~225 m.

Finally, I decided to try moving around. I got fascinated by the huge jump in data rate as I move across the sim boundry, right near my front door. Starting at the southeast corner of my home sim (Solway), 0.06 GB/hr, step acroos the boundry  and it jumps to 0.41!  Stepping back and forth acrossthe sim boundry 111 m to the north, essentially the same jump. But continuing north along the western edge Lanercost, the data rate drops abruptly at 125 m, down to about the same level as in the adjacent sim. No more jump in data rate crossing the boundry east/west. As I walk north to south and back along the border in Solway, nothin happens to the data rate. In the lanercost sim, there is this huge step in data rate near 120 m. Then, since  I was in a 4-corner area, I looked at the sims just to the north of Solway and Lanercost. The southeast corner of Pernit shows high data rate, with an abbrupt, reversable step crossing back and forth from there to Pernith, or from there to Solway.  (Solway was running LeTigre 12.08.17.263666, all others SL server 12.08.14.263480)

So what did I learn from the execise?   Well, I learned that factor of 5 changes in data rate are not uncommon in SL, with big jumps coming both with position and draw distance. There is nothing gradual about these steps, they are sharp. It turns out, I had my draw distance set to 300 m while I was on my road trip.  When I am on the road next time, I will keep my draw distance down to 96 m, and I will keep an eye on the network monitor to make sure than one of my favorite places has not changed into a data hog.

 

[Theresa Tennyson]

You're seeing the bug described in JIRA entries SVC-8124 and SVC-8155. There's a fix but it may not be released to the main grid next Tuesday for seemingly unrelated reasons.

[shug Maitland]

I have noticed the same things you have, but not in such detail, thanks for the work.

I have taken to keeping my draw distance at 192M, just short of the big jump and the statistics floater open. You are right about the abruptness of the jump, it also manifests in location, before the last RC restarts I had defined a line showing a roughly square area in the SW corner of Brocade with a jump of ~1000kbps with draw distance at 32M! The diagonal region seems to be key (in my case it was LeTigre).

[161488303349]

thanks

[mikka Luik]

Thanks for providing this, appreciated

[Starr Heron]

Something wrong with draw distance. My one property runs at 1200 kbps at draw distance 256m

my other 100 kbps at 256m. If i turn down draw to 32m I get 30kbps on both lots.

Not very enjoyable at 32m but atleast I can do what needs to be done with my breedables.