p1400: use `git-update-ref --stdin` to test multiple transactions

In commit 0a0fbbe3ff (refs: remove lookup cache for
reference-transaction hook, 2020-08-25), a new benchmark was added to
p1400 which has the intention to exercise creation of multiple
transactions in a single process. As git-update-ref wasn't yet able to
create multiple transactions with a single run we instead used git-push.
As its non-atomic version creates a transaction per reference update,
this was the best approximation we could make at that point in time.

Now that `git-update-ref --stdin` supports creation of multiple
transactions, let's convert the benchmark to use that instead. It has
less overhead and it's also a lot clearer what the actual intention is.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/perf/p1400-update-ref.sh b/t/perf/p1400-update-ref.sh
index ce5ac3ed85e10efc2b4dd784e5d8949d8f269a75..dda8a7486634488d65ca30ca6da1e795c4eb3a3a 100755 (executable)
--- a/t/perf/p1400-update-ref.sh
+++ b/t/perf/p1400-update-ref.sh
@@ -7,13 +7,14 @@ test_description="Tests performance of update-ref"
 test_perf_fresh_repo
 
 test_expect_success "setup" '
-       git init --bare target-repo.git &&
        test_commit PRE &&
        test_commit POST &&
-       printf "create refs/heads/%d PRE\n" $(test_seq 1000) >create &&
-       printf "update refs/heads/%d POST PRE\n" $(test_seq 1000) >update &&
-       printf "delete refs/heads/%d POST\n" $(test_seq 1000) >delete &&
-       git update-ref --stdin <create
+       for i in $(test_seq 5000)
+       do
+               printf "start\ncreate refs/heads/%d PRE\ncommit\n" $i &&
+               printf "start\nupdate refs/heads/%d POST PRE\ncommit\n" $i &&
+               printf "start\ndelete refs/heads/%d POST\ncommit\n" $i
+       done >instructions
 '
 
 test_perf "update-ref" '
@@ -26,14 +27,7 @@ test_perf "update-ref" '
 '
 
 test_perf "update-ref --stdin" '
-       git update-ref --stdin <update &&
-       git update-ref --stdin <delete &&
-       git update-ref --stdin <create
-'
-
-test_perf "nonatomic push" '
-       git push ./target-repo.git $(test_seq 1000) &&
-       git push --delete ./target-repo.git $(test_seq 1000)
+       git update-ref --stdin <instructions >/dev/null
 '
 
 test_done