On Wed, Aug 25 2021, Patrick Steinhardt wrote:
> [[PGP Signed Part:Undecided]]
> When fetching, Git will by default print a list of all updated refs in a
> nicely formatted table. In order to come up with this table, Git needs
> to iterate refs twice: first to determine the maximum column width, and
> a second time to actually format these changed refs.
>
> While this table will not be printed in case the user passes `--quiet`,
> we still go out of our way and do all these steps. In fact, we even do
> more work compared to not passing `--quiet`: without the flag, we will
> skip all references in the column width computation which have not been
> updated, but if it is set we will now compute widths for all refs.
>
> Fix this issue by completely skipping both preparation of the format and
> formatting data for display in case the user passes `--quiet`, improving
> performance especially with many refs. The following benchmark shows a
> nice speedup for a quiet mirror-fetch in a repository with 2.3M refs:
>
> Benchmark #1: HEAD~: git-fetch
> Time (mean ± σ): 26.929 s ± 0.145 s [User: 24.194 s, System: 4.656 s]
> Range (min … max): 26.692 s … 27.068 s 5 runs
>
> Benchmark #2: HEAD: git-fetch
> Time (mean ± σ): 25.189 s ± 0.094 s [User: 22.556 s, System: 4.606 s]
> Range (min … max): 25.070 s … 25.314 s 5 runs
>
> Summary
> 'HEAD: git-fetch' ran
> 1.07 ± 0.01 times faster than 'HEAD~: git-fetch'
>
> Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
> ---
> builtin/fetch.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/fetch.c b/builtin/fetch.c
> index e064687dbd..d064b66512 100644
> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -757,6 +757,9 @@ static void prepare_format_display(struct ref *ref_map)
> die(_("configuration fetch.output contains invalid value %s"),
> format);
>
> + if (verbosity < 0)
> + return;
> +
> for (rm = ref_map; rm; rm = rm->next) {
> if (rm->status == REF_STATUS_REJECT_SHALLOW ||
> !rm->peer_ref ||
> @@ -827,7 +830,12 @@ static void format_display(struct strbuf *display, char code,
> const char *remote, const char *local,
> int summary_width)
> {
> - int width = (summary_width + strlen(summary) - gettext_width(summary));
> + int width;
> +
> + if (verbosity < 0)
> + return;
> +
> + width = (summary_width + strlen(summary) - gettext_width(summary));
>
> strbuf_addf(display, "%c %-*s ", code, width, summary);
> if (!compact_format)
I wonder what you think of the below, which is a bit more of a verbose
search/replacement change, but I think ultimately cleaner. We just pass
the "ref_map" down to all the formatting functions, and the first
function that needs to know the "compact_format" or "refcol_width"
lazily computes it (stored in a static variable). So we avoid the tricky
action at a distance of not preparing certain things because we know
we're in the quiet mode.
But if I understand your change correctly we're on the one hand not
preparing the format change, but then also not printing this at all now
under --quiet, correct? I think it would be good to split up that
proposed functional change from the optimization of the output, it also
seems like if that were done the git-fetch docs on --quiet need to be
changed.
But I wonder if once we have the change below, whether the small change
on top of it to just add a fetch.outputRefWidth=123 wouldn't also
largely solve the optimization problem you have, i.e. adding a config
variable to adjust the width, instead of us auto-discovering it by
looping over all refs.
Or maybe not, but I think it would be interesting to see how much of the
slowdown you have is that v.s. that we end up emitting this output to
stderr. I.e. is it the I/O of the output or the extra loop that's the
expensive part?
diff --git a/builtin/fetch.c b/builtin/fetch.c
index e064687dbdc..88a8b3660d4 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -707,6 +707,24 @@ static int s_update_ref(const char *action,
static int refcol_width = 10;
static int compact_format;
+static int prepared_compact_format;
+static void prepare_compact_format(void)
+{
+ const char *format = "full";
+
+ if (prepared_compact_format++)
+ return;
+
+ git_config_get_string_tmp("fetch.output", &format);
+ if (!strcasecmp(format, "full"))
+ compact_format = 0;
+ else if (!strcasecmp(format, "compact"))
+ compact_format = 1;
+ else
+ die(_("configuration fetch.output contains invalid value %s"),
+ format);
+}
+
static void adjust_refcol_width(const struct ref *ref)
{
int max, rlen, llen, len;
@@ -726,6 +744,7 @@ static void adjust_refcol_width(const struct ref *ref)
* anyway because we don't know if the error explanation part
* will be printed in update_local_ref)
*/
+ prepare_compact_format();
if (compact_format) {
llen = 0;
max = max * 2 / 3;
@@ -743,19 +762,13 @@ static void adjust_refcol_width(const struct ref *ref)
refcol_width = rlen;
}
-static void prepare_format_display(struct ref *ref_map)
+static int prepared_refcol_width;
+static void prepare_refcol_width(struct ref *ref_map)
{
struct ref *rm;
- const char *format = "full";
- git_config_get_string_tmp("fetch.output", &format);
- if (!strcasecmp(format, "full"))
- compact_format = 0;
- else if (!strcasecmp(format, "compact"))
- compact_format = 1;
- else
- die(_("configuration fetch.output contains invalid value %s"),
- format);
+ if (prepared_refcol_width++)
+ return;
for (rm = ref_map; rm; rm = rm->next) {
if (rm->status == REF_STATUS_REJECT_SHALLOW ||
@@ -767,9 +780,10 @@ static void prepare_format_display(struct ref *ref_map)
}
}
-static void print_remote_to_local(struct strbuf *display,
+static void print_remote_to_local(struct ref *ref_map, struct strbuf *display,
const char *remote, const char *local)
{
+ prepare_refcol_width(ref_map);
strbuf_addf(display, "%-*s -> %s", refcol_width, remote, local);
}
@@ -800,7 +814,7 @@ static int find_and_replace(struct strbuf *haystack,
return 1;
}
-static void print_compact(struct strbuf *display,
+static void print_compact(struct ref *ref_map, struct strbuf *display,
const char *remote, const char *local)
{
struct strbuf r = STRBUF_INIT;
@@ -816,13 +830,14 @@ static void print_compact(struct strbuf *display,
if (!find_and_replace(&r, local, "*"))
find_and_replace(&l, remote, "*");
- print_remote_to_local(display, r.buf, l.buf);
+ print_remote_to_local(ref_map, display, r.buf, l.buf);
strbuf_release(&r);
strbuf_release(&l);
}
-static void format_display(struct strbuf *display, char code,
+static void format_display(struct ref *ref_map,
+ struct strbuf *display, char code,
const char *summary, const char *error,
const char *remote, const char *local,
int summary_width)
@@ -830,15 +845,17 @@ static void format_display(struct strbuf *display, char code,
int width = (summary_width + strlen(summary) - gettext_width(summary));
strbuf_addf(display, "%c %-*s ", code, width, summary);
+ prepare_compact_format();
if (!compact_format)
- print_remote_to_local(display, remote, local);
+ print_remote_to_local(ref_map, display, remote, local);
else
- print_compact(display, remote, local);
+ print_compact(ref_map, display, remote, local);
if (error)
strbuf_addf(display, " (%s)", error);
}
-static int update_local_ref(struct ref *ref,
+static int update_local_ref(struct ref *ref_map,
+ struct ref *ref,
struct ref_transaction *transaction,
const char *remote,
const struct ref *remote_ref,
@@ -857,7 +874,7 @@ static int update_local_ref(struct ref *ref,
if (oideq(&ref->old_oid, &ref->new_oid)) {
if (verbosity > 0)
- format_display(display, '=', _("[up to date]"), NULL,
+ format_display(ref_map, display, '=', _("[up to date]"), NULL,
remote, pretty_ref, summary_width);
return 0;
}
@@ -870,7 +887,7 @@ static int update_local_ref(struct ref *ref,
* If this is the head, and it's not okay to update
* the head, and the old value of the head isn't empty...
*/
- format_display(display, '!', _("[rejected]"),
+ format_display(ref_map, display, '!', _("[rejected]"),
_("can't fetch in current branch"),
remote, pretty_ref, summary_width);
return 1;
@@ -881,12 +898,12 @@ static int update_local_ref(struct ref *ref,
if (force || ref->force) {
int r;
r = s_update_ref("updating tag", ref, transaction, 0);
- format_display(display, r ? '!' : 't', _("[tag update]"),
+ format_display(ref_map, display, r ? '!' : 't', _("[tag update]"),
r ? _("unable to update local ref") : NULL,
remote, pretty_ref, summary_width);
return r;
} else {
- format_display(display, '!', _("[rejected]"), _("would clobber existing tag"),
+ format_display(ref_map, display, '!', _("[rejected]"), _("would clobber existing tag"),
remote, pretty_ref, summary_width);
return 1;
}
@@ -918,7 +935,7 @@ static int update_local_ref(struct ref *ref,
}
r = s_update_ref(msg, ref, transaction, 0);
- format_display(display, r ? '!' : '*', what,
+ format_display(ref_map, display, r ? '!' : '*', what,
r ? _("unable to update local ref") : NULL,
remote, pretty_ref, summary_width);
return r;
@@ -940,7 +957,7 @@ static int update_local_ref(struct ref *ref,
strbuf_addstr(&quickref, "..");
strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
r = s_update_ref("fast-forward", ref, transaction, 1);
- format_display(display, r ? '!' : ' ', quickref.buf,
+ format_display(ref_map, display, r ? '!' : ' ', quickref.buf,
r ? _("unable to update local ref") : NULL,
remote, pretty_ref, summary_width);
strbuf_release(&quickref);
@@ -952,13 +969,13 @@ static int update_local_ref(struct ref *ref,
strbuf_addstr(&quickref, "...");
strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
r = s_update_ref("forced-update", ref, transaction, 1);
- format_display(display, r ? '!' : '+', quickref.buf,
+ format_display(ref_map, display, r ? '!' : '+', quickref.buf,
r ? _("unable to update local ref") : _("forced update"),
remote, pretty_ref, summary_width);
strbuf_release(&quickref);
return r;
} else {
- format_display(display, '!', _("[rejected]"), _("non-fast-forward"),
+ format_display(ref_map, display, '!', _("[rejected]"), _("non-fast-forward"),
remote, pretty_ref, summary_width);
return 1;
}
@@ -1111,8 +1128,6 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
}
}
- prepare_format_display(ref_map);
-
/*
* We do a pass for each fetch_head_status type in their enum order, so
* merged entries are written before not-for-merge. That lets readers
@@ -1187,8 +1202,9 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
strbuf_reset(¬e);
if (ref) {
- rc |= update_local_ref(ref, transaction, what,
- rm, ¬e, summary_width);
+ rc |= update_local_ref(ref_map, ref,
+ transaction, what, rm,
+ ¬e, summary_width);
free(ref);
} else if (write_fetch_head || dry_run) {
/*
@@ -1196,7 +1212,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
* would be written to FETCH_HEAD, if --dry-run
* is set).
*/
- format_display(¬e, '*',
+ format_display(ref_map, ¬e, '*',
*kind ? kind : "branch", NULL,
*what ? what : "HEAD",
"FETCH_HEAD", summary_width);
@@ -1357,7 +1373,7 @@ static int prune_refs(struct refspec *rs, struct ref *ref_map,
fprintf(stderr, _("From %.*s\n"), url_len, url);
shown_url = 1;
}
- format_display(&sb, '-', _("[deleted]"), NULL,
+ format_display(ref_map, &sb, '-', _("[deleted]"), NULL,
_("(none)"), prettify_refname(ref->name),
summary_width);
fprintf(stderr, " %s\n",sb.buf);
