Mike Hommey <m...@glandium.org> wrote: > I'm puzzled by the fact writing objects is so much faster with 1 thread.
I/O contention in the multi-threaded cases? "public-inbox-index" (reading from git, writing to Xapian+SQLite) on a dev machine got slow because core count exceeded what SATA could handle and had to cap the default Xapian shard count to 3 by default for v2 inboxes. As for memory use, does git use the producer/consumer pattern for malloc+free so free happens in a different thread from the malloc? Because current versions of glibc gets pathological with that case (but I have a long-term fix for it): https://public-inbox.org/libc-alpha/20180731084936.g4yw6wnvt677miti@dcvr/T/ Only locklessinc malloc seemed OK in the IPC department (But I haven't kept up with jemalloc, tcmalloc developments in years)
