git only writing 4k at a time

Hiya list,

I've been investigating some performance issues around git clones over network mounts. We have noticed that git is only writing 4k at a time. These small serial writes are making it such that even though each write is only a 3ms operation, the total time balloons. Looking around the source code I found that reftable_writer is initialized by default (though I cannot find the block_size argument being supplied in my cursory look) always to DEFAULT_BLOCK_SIZE (4096). Is there some way to increase/configure this block size such that larger writes happen? In git/Documentation/config/reftable.adoc this block size is mentioned in a manner that almost feels configurable, but I'm not sure if this is just internal for development.

Thanks, ~ Haylin Moore