Duy Nguyen <pclo...@gmail.com> writes: > On Thu, Mar 20, 2014 at 5:11 AM, Junio C Hamano <gits...@pobox.com> wrote: > ... >> I know that the 512MiB default for the bitFileThreashold (aka >> "forget about delta compression") came out of thin air. It was just >> "1GB is always too huge for anybody, so let's cut it in half and >> declare that value the initial version of a sane threashold", >> nothing more. >> >> So it might be that the problem is 512MiB is still too big, relative >> to the 16MiB of delta base cache, and the former may be what needs >> to be tweaked. If a blob close to but below 512MiB is a problem for >> 16MiB delta base cache, it would still be too big to cause the same >> problem for 128MiB delta base cache---it would evict all the other >> objects and then end up not being able to fit in the limit itself, >> busting the limit immediately, no? >> >> I would understand if the change were to update the definition of >> deltaBaseCacheLimit and link it to the value of bigFileThreashold, >> for example. With the presented discussion, I am still not sure if >> we can say that bumping deltaBaseCacheLimit is the right solution to >> the "description with the current setting is clearly wrong" (which >> is a real issue). > > I vote make big_file_threshold smaller. 512MB is already unfriendly > for many smaller machines. I'm thinking somewhere around 32MB-64MB > (and maybe increase delta cache base limit to match).
These numbers match my gut feeling (e.g. 4k*4k*32-bit uncompressed would be 64MB); delta cash base that is sized to the same as (or perhaps twice as big as) that limit may be a good default. > The only > downside I see is large blobs will be packed undeltified, which could > increase pack size if you have lots of them. I think that is something that can be tweaked, unless the user tells us otherwise via command line override, when running the improved "gc --aggressive" ;-) -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
