[darcs-users] no more checkpoints, but hashed repos for GHC in Darcs 2.4?
me at mornfall.net
Thu Sep 17 16:40:11 UTC 2009
Eric Kow <kowey at darcs.net> writes:
>> - http://bugs.darcs.net/issue1589 (7-second overhead for pulling
>> or unpulling one patch)
> This one still needs attention.
> We've pretty much verified that this is slow with hashed repositories
> and fast with old-fashioned repositories. OK one second comes from the
> deliberate delay and maybe the extra 6 comes from needless inventory
I'll look at it. It may as well be that we are calling clean_hashdir, which is
very slow, especially with large cache (and although I made it a lot faster in
darcs-hs, it'll still take much longer than the equivalent operation in
old-fashioned, which is nil).
>> - timestamps getting out of sync by hard-linking the hashed pristine files.
>> I presume this is fixed by darcs-hs anyway.
> I believe that for projects with branches, fixing this is where the
> biggest positive impact from hashed-storage will be (Rah!).
>> - dividing the cache into subdirectories to avoid bad filesystem
>> performance with large directories.
> That's http://bugs.darcs.net/issue1536 :-)
> Petr: how do you feel about this? Do you rate this as being easier
> than packs? Is it realistic to want this in Darcs 2.4? I am also
> concerned about backward compatibility. How do we handle this? Format
For cache, this should be quite simple. For repos, this would be incompatible
change and we probably can't afford to do it just yet.
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