revset: use `subset &` in `outgoing` This should give us the same benefit as elsewhere. Result is simpler (and "faster"). Outgoing is dominated by the discovery so no benchmark is provided.

revset: avoid in loop lookup in _generatorset._consumegen Python lookups are slow, so do all lookup outside of the for loop. This provide a small but still significant speedup: revset #0: 0:: 0) wall 0.063258 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) 1) wall 0.057776 comb 0.050000 user 0.050000 sys 0.000000 (best of 100)

revset: reduce dict lookup in lazyset.__contains__ Avoid an extra dict lookup when we have to compute the value. No visible performance impact but this shaves the yak a few extra nanometers.

revset: do less lookup during spanset.__contains__ Attribute lookup is slow in python. So this version is going to be a bit faster. This does not have a visible impact since the rest of the stack is much slower but this shaves the yak a few extra nanometers. Moreover the new version is more readable so it worth doing this change for code quality purpose. This optimisation was approved by a core python dev.

largefiles: simplify iteration over standins Instead of iterating over all files in the context and ignoring those that are not standins, pass a standin-matcher to the context and iterate over only the files matching. Apart from making the intent clearer, this implementation will also benefit from any future optimizations done to the manifest walking code.

largefiles: avoid using 'lfiles' variable for two purposes The variable 'lfiles' is first used for a set of the names of all the large files. It is then overwritten with a tuple like the ones returned from status(). To reduce confusion, let's create a separate variable for the second use.