| Message ID | d3dac607f2235c5913621813c443aa10b99c8fe8.1629452412.git.ps@pks.im (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Speed up mirror-fetches with many refs | expand |
On Fri, Aug 20 2021, Patrick Steinhardt wrote: > [[PGP Signed Part:Undecided]] > When updating local refs after the fetch has transferred all objects, we > do an object existence test as a safety guard to avoid updating a ref to > an object which we don't have. We do so via `oid_object_info()`: if it > returns an error, then we know the object does not exist. > > One side effect of `oid_object_info()` is that it parses the object's > type, and to do so it must unpack the object header. This is completely > pointless: we don't care for the type, but only want to assert that the > object exists. > > Refactor the code to use `repo_has_object_file()`, which both makes the > code's intent clearer and is also faster because it does not unpack > object headers. In a real-world repo with 2.3M refs, this results in a > small speedup when doing a mirror-fetch: > > Benchmark #1: HEAD~: git-fetch > Time (mean ± σ): 33.686 s ± 0.176 s [User: 30.119 s, System: 5.262 s] > Range (min … max): 33.512 s … 33.944 s 5 runs > > Benchmark #2: HEAD: git-fetch > Time (mean ± σ): 31.247 s ± 0.195 s [User: 28.135 s, System: 5.066 s] > Range (min … max): 30.948 s … 31.472 s 5 runs > > Summary > 'HEAD: git-fetch' ran > 1.08 ± 0.01 times faster than 'HEAD~: git-fetch' > > Signed-off-by: Patrick Steinhardt <ps@pks.im> > --- > builtin/fetch.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/builtin/fetch.c b/builtin/fetch.c > index 73f5b286d5..5fd0f7c791 100644 > --- a/builtin/fetch.c > +++ b/builtin/fetch.c > @@ -846,13 +846,11 @@ static int update_local_ref(struct ref *ref, > int summary_width) > { > struct commit *current = NULL, *updated; > - enum object_type type; > struct branch *current_branch = branch_get(NULL); > const char *pretty_ref = prettify_refname(ref->name); > int fast_forward = 0; > > - type = oid_object_info(the_repository, &ref->new_oid, NULL); > - if (type < 0) > + if (!repo_has_object_file(the_repository, &ref->new_oid)) > die(_("object %s not found"), oid_to_hex(&ref->new_oid)); > > if (oideq(&ref->old_oid, &ref->new_oid)) { I tried grepping the source for any other candidates for a migration to repo_has_object_file(), but this is the only "type = oid_object_info" I could find that didn't care about the type, perhaps there's some callers of *_extended() that could be moved over, but that's less likely, and I didn't check...
diff --git a/builtin/fetch.c b/builtin/fetch.c index 73f5b286d5..5fd0f7c791 100644 --- a/builtin/fetch.c +++ b/builtin/fetch.c @@ -846,13 +846,11 @@ static int update_local_ref(struct ref *ref, int summary_width) { struct commit *current = NULL, *updated; - enum object_type type; struct branch *current_branch = branch_get(NULL); const char *pretty_ref = prettify_refname(ref->name); int fast_forward = 0; - type = oid_object_info(the_repository, &ref->new_oid, NULL); - if (type < 0) + if (!repo_has_object_file(the_repository, &ref->new_oid)) die(_("object %s not found"), oid_to_hex(&ref->new_oid)); if (oideq(&ref->old_oid, &ref->new_oid)) {
When updating local refs after the fetch has transferred all objects, we do an object existence test as a safety guard to avoid updating a ref to an object which we don't have. We do so via `oid_object_info()`: if it returns an error, then we know the object does not exist. One side effect of `oid_object_info()` is that it parses the object's type, and to do so it must unpack the object header. This is completely pointless: we don't care for the type, but only want to assert that the object exists. Refactor the code to use `repo_has_object_file()`, which both makes the code's intent clearer and is also faster because it does not unpack object headers. In a real-world repo with 2.3M refs, this results in a small speedup when doing a mirror-fetch: Benchmark #1: HEAD~: git-fetch Time (mean ± σ): 33.686 s ± 0.176 s [User: 30.119 s, System: 5.262 s] Range (min … max): 33.512 s … 33.944 s 5 runs Benchmark #2: HEAD: git-fetch Time (mean ± σ): 31.247 s ± 0.195 s [User: 28.135 s, System: 5.066 s] Range (min … max): 30.948 s … 31.472 s 5 runs Summary 'HEAD: git-fetch' ran 1.08 ± 0.01 times faster than 'HEAD~: git-fetch' Signed-off-by: Patrick Steinhardt <ps@pks.im> --- builtin/fetch.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)