so far not much ...

both Saudi and China need to sell US t-notes and t-bonds to support domestic initiatives. funny thing is China can sell for a high price b/c of flight to safey due to RMB devaluation and domestic equity mkt dive. 

so far treasury yield is stable, partially due to flight to safety effect. the meager 2% 10Y t-note yield is still several times higher than that of German bund across the pond.

the bigger effect on yield lies in Fed policy to end zero interest rate policy (ZIRP) and hike Federal Fund (FF) rate. that is why mkt is fixating on Jackson Hole. Fed however is playing both side (in their words, policy is "data-dependent") and talks from both sides of its mouth as well. If equity mkt stays depressed Fed likely will delay first rate hike for FF rate. A fast recovery on the other hand, brings Sep raise back on the table. 

another way to think about China and Saudi selling is to look at it as a reverse QE. Sincer QE ended last Dec, backend rate is stable or slightly down. the immediate and intermediate effects on rate are likely to be minor, especially given Europe's onging QE program. If US economy slows down, it is caused by lack of demand domoestically and slow growth/recovery internationally, instead of higher interest rate caused by China and Saudi selling.

Slow growth leads to a lower yield level as well. Fed's pace of FF rate hike will also be slowed down, which further offsets foreign selling of US treasuries. Worst comes to worst, nothing prevents Fed to start another round of QE program. QE, like other sins, is addictive. 

just my 2c