ZheNing Hu via GitGitGadget <gitgitgadget@xxxxxxxxx> 于2021年4月9日周五 下午9:35写道： > > From: ZheNing Hu <adlternative@xxxxxxxxx> > > When we use `git for-each-ref`, every ref will call > `show_ref_array_item()` and allocate its own final strbuf. > But we can reuse the final strbuf for each step ref's output. > Since `show_ref_array_item()` is not used in many places, > we can directly delete `show_ref_array_item()` and use the > same logic code to replace it. In this way, the caller can > clearly see how the loop work. > > The performance for `git for-each-ref` on the Git repository > itself with performance testing tool `hyperfine` changes from > 23.7 ms ± 0.9 ms to 22.2 ms ± 1.0 ms. > > At the same time, we apply this optimization to `git tag -l` > and `git branch -l`, the `git branch -l` performance upgrade > from 5.8 ms ± 0.8 ms to 2.7 ms ± 0.2 ms and `git tag -l` > performance upgrade from 5.9 ms ± 0.4 ms to 5.4 ms ± 0.4 ms. > Since the number of tags in git.git is much more than branches, > so this shows that the optimization will be more obvious in > those repositories that contain a small number of objects. > > This approach is similar to the one used by 79ed0a5 > (cat-file: use a single strbuf for all output, 2018-08-14) > to speed up the cat-file builtin. > > Signed-off-by: ZheNing Hu <adlternative@xxxxxxxxx> > --- > [GSOC] ref-filter: get rid of show_ref_array_item > > Now git for-each-ref can reuse final buf for all refs output, the > performance is slightly improved, This optimization is also applied to > git tag -l and git branch -l. > > Thanks. > > Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-928%2Fadlternative%2Fref-filter-reuse-buf-v1 > Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-928/adlternative/ref-filter-reuse-buf-v1 > Pull-Request: https://github.com/gitgitgadget/git/pull/928 > > builtin/branch.c | 8 ++++---- > builtin/for-each-ref.c | 13 +++++++++++-- > builtin/tag.c | 13 +++++++++++-- > ref-filter.c | 24 +++++++++--------------- > ref-filter.h | 2 -- > 5 files changed, 35 insertions(+), 25 deletions(-) > > diff --git a/builtin/branch.c b/builtin/branch.c > index bcc00bcf182d..5c797e992aa4 100644 > --- a/builtin/branch.c > +++ b/builtin/branch.c > @@ -411,6 +411,8 @@ static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sortin > { > int i; > struct ref_array array; > + struct strbuf out = STRBUF_INIT; > + struct strbuf err = STRBUF_INIT; > int maxwidth = 0; > const char *remote_prefix = ""; > char *to_free = NULL; > @@ -440,8 +442,7 @@ static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sortin > ref_array_sort(sorting, &array); > > for (i = 0; i < array.nr; i++) { > - struct strbuf out = STRBUF_INIT; > - struct strbuf err = STRBUF_INIT; > + strbuf_reset(&out); > if (format_ref_array_item(array.items[i], format, &out, &err)) > die("%s", err.buf); > if (column_active(colopts)) { > @@ -452,10 +453,9 @@ static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sortin > fwrite(out.buf, 1, out.len, stdout); > putchar('\n'); > } > - strbuf_release(&err); > - strbuf_release(&out); > } > > + strbuf_release(&out); > ref_array_clear(&array); > free(to_free); > } > diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c > index cb9c81a04606..157cc8623949 100644 > --- a/builtin/for-each-ref.c > +++ b/builtin/for-each-ref.c > @@ -22,6 +22,8 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix) > struct ref_array array; > struct ref_filter filter; > struct ref_format format = REF_FORMAT_INIT; > + struct strbuf output = STRBUF_INIT; > + struct strbuf err = STRBUF_INIT; > > struct option opts[] = { > OPT_BIT('s', "shell", &format.quote_style, > @@ -80,8 +82,15 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix) > > if (!maxcount || array.nr < maxcount) > maxcount = array.nr; > - for (i = 0; i < maxcount; i++) > - show_ref_array_item(array.items[i], &format); > + for (i = 0; i < maxcount; i++) { > + strbuf_reset(&output); > + if (format_ref_array_item(array.items[i], &format, &output, &err)) > + die("%s", err.buf); > + fwrite(output.buf, 1, output.len, stdout); > + putchar('\n'); > + } > + > + strbuf_release(&output); > ref_array_clear(&array); > return 0; > } > diff --git a/builtin/tag.c b/builtin/tag.c > index d403417b5625..b172f3861413 100644 > --- a/builtin/tag.c > +++ b/builtin/tag.c > @@ -39,6 +39,8 @@ static int list_tags(struct ref_filter *filter, struct ref_sorting *sorting, > struct ref_format *format) > { > struct ref_array array; > + struct strbuf output = STRBUF_INIT; > + struct strbuf err = STRBUF_INIT; > char *to_free = NULL; > int i; > > @@ -63,8 +65,15 @@ static int list_tags(struct ref_filter *filter, struct ref_sorting *sorting, > filter_refs(&array, filter, FILTER_REFS_TAGS); > ref_array_sort(sorting, &array); > > - for (i = 0; i < array.nr; i++) > - show_ref_array_item(array.items[i], format); > + for (i = 0; i < array.nr; i++) { > + strbuf_reset(&output); > + if (format_ref_array_item(array.items[i], format, &output, &err)) > + die("%s", err.buf); > + fwrite(output.buf, 1, output.len, stdout); > + putchar('\n'); > + } > + > + strbuf_release(&output); > ref_array_clear(&array); > free(to_free); > > diff --git a/ref-filter.c b/ref-filter.c > index f0bd32f71416..9e38e42fb7ae 100644 > --- a/ref-filter.c > +++ b/ref-filter.c > @@ -2435,27 +2435,21 @@ int format_ref_array_item(struct ref_array_item *info, > return 0; > } > > -void show_ref_array_item(struct ref_array_item *info, > - const struct ref_format *format) > -{ > - struct strbuf final_buf = STRBUF_INIT; > - struct strbuf error_buf = STRBUF_INIT; > - > - if (format_ref_array_item(info, format, &final_buf, &error_buf)) > - die("%s", error_buf.buf); > - fwrite(final_buf.buf, 1, final_buf.len, stdout); > - strbuf_release(&error_buf); > - strbuf_release(&final_buf); > - putchar('\n'); > -} > - > void pretty_print_ref(const char *name, const struct object_id *oid, > const struct ref_format *format) > { > struct ref_array_item *ref_item; > + struct strbuf output = STRBUF_INIT; > + struct strbuf err = STRBUF_INIT; > + > ref_item = new_ref_array_item(name, oid); > ref_item->kind = ref_kind_from_refname(name); > - show_ref_array_item(ref_item, format); > + if (format_ref_array_item(ref_item, format, &output, &err)) > + die("%s", err.buf); > + fwrite(output.buf, 1, output.len, stdout); > + putchar('\n'); > + > + strbuf_release(&output); > free_array_item(ref_item); > } > > diff --git a/ref-filter.h b/ref-filter.h > index 19ea4c413409..baf72a718965 100644 > --- a/ref-filter.h > +++ b/ref-filter.h > @@ -119,8 +119,6 @@ int format_ref_array_item(struct ref_array_item *info, > const struct ref_format *format, > struct strbuf *final_buf, > struct strbuf *error_buf); > -/* Print the ref using the given format and quote_style */ > -void show_ref_array_item(struct ref_array_item *info, const struct ref_format *format); > /* Parse a single sort specifier and add it to the list */ > void parse_ref_sorting(struct ref_sorting **sorting_tail, const char *atom); > /* Callback function for parsing the sort option */ > > base-commit: 2e36527f23b7f6ae15e6f21ac3b08bf3fed6ee48 > -- > gitgitgadget The patch seems to have fallen into the crack. Jeff and Junio, willing to help? Thanks! -- ZheNing Hu
