BF-22597 shows a 27% performance improvement for Test: ycsb_50read50update within Task: ycsb_60GB.  A graph of the drop can be seen in the BF ticket (or at here and select ycsb_50read50update with measurement "Data - disk xvde disk written (writes/s) - mean")

The improvement corresponds to the merge of the single ticket WT-7853, that ticket keeps a list of updates during reconciliation in order to accurately tag them with WT_UPDATE_DS or not.

Originally we thought this was a performance degradation, so I made this suggestion, which we still might consider:  A guess about the performance drop are the new calls to __wt_calloc and __wt_free.  We might look into using scratch memory (__wt_scr_alloc_ and __wt_scr_free ) if the list is created and freed in a single thread, or possibly allocating/extending an array of WT_UPDATE_CACHE items instead of one at a time.

I'm leaving this ticket open to consider this change and also to make sure we understand the performance improvement.