From: Kyle Zhao via GitGitGadget Date: Thu, 16 Jun 2022 03:36:57 GMT Subject: [PATCH v2] send-pack.c: add config push.useBitmaps Message-ID: In-Reply-To: From: Kyle Zhao This allows you to disable bitmaps for "git push". Default is false. Reachability bitmaps are designed to speed up the "counting objects" phase of generating a pack during a clone or fetch. They are not optimized for Git clients sending a small topic branch via "git push". In some cases (see [1]), using reachability bitmaps during "git push" can cause significant performance regressions. Add a new "push.useBitmaps" config option to disable reachability bitmaps during "git push". This allows reachability bitmaps to still be used in other areas, such as "git rev-list --use-bitmap-index". [1]: https://lore.kernel.org/git/87zhoz8b9o.fsf@evledraar.gmail.com/ Signed-off-by: Kyle Zhao --- send-pack.c: add config push.useBitmaps This patch add config push.useBitmaps to prevent git push using bitmap. The origin discussion is here: https://lore.kernel.org/git/b940e705fbe9454685757f2e3055e2ce@tencent.com/ Thanks, -Kyle Changes since v1: * changed the commit message * modified and added missing \n to push.txt * used test_subcommand for test * modified "if" statement for "git_config_get_bool()" in send-pack.c Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1263%2Fkeyu98%2Fkz%2Fpush-usebitmps-config-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1263/keyu98/kz/push-usebitmps-config-v2 Pull-Request: https://github.com/gitgitgadget/git/pull/1263 Range-diff vs v1: 1: 000d033584b ! 1: 42e0b4845b2 send-pack.c: add config push.useBitmaps @@ Metadata ## Commit message ## send-pack.c: add config push.useBitmaps - This allows you to disabled bitmaps for "git push". Default is false. + This allows you to disable bitmaps for "git push". Default is false. - Bitmaps are designed to speed up the "counting objects" phase of - subsequent packs created for clones and fetches. - But in some cases, turning bitmaps on does horrible things for "push" - performance[1]. + Reachability bitmaps are designed to speed up the "counting objects" + phase of generating a pack during a clone or fetch. They are not + optimized for Git clients sending a small topic branch via "git push". + In some cases (see [1]), using reachability bitmaps during "git push" + can cause significant performance regressions. + + Add a new "push.useBitmaps" config option to disable reachability + bitmaps during "git push". This allows reachability bitmaps to still + be used in other areas, such as "git rev-list --use-bitmap-index". [1]: https://lore.kernel.org/git/87zhoz8b9o.fsf@evledraar.gmail.com/ @@ Documentation/config/push.txt: push.negotiate:: in common. + +push.useBitmaps:: -+ If this config and `pack.useBitmaps` are both "true", git will -+ use pack bitmaps (if available) when git push. Default is false. - \ No newline at end of file ++ If this config and `pack.useBitmaps` are both `true`, then Git will ++ use reachability bitmaps during `git push`, if available (disabled ++ by default). ## send-pack.c ## @@ send-pack.c: static int pack_objects(int fd, struct ref *refs, struct oid_array *advertised, @@ send-pack.c: static int pack_objects(int fd, struct ref *refs, struct oid_array po.out = args->stateless_rpc ? -1 : fd; po.git_cmd = 1; @@ send-pack.c: int send_pack(struct send_pack_args *args, - int use_push_options = 0; - int push_options_supported = 0; - int object_format_supported = 0; -+ int use_bitmaps = 0; - unsigned cmds_sent = 0; - int ret; struct async demux; + const char *push_cert_nonce = NULL; + struct packet_reader reader; ++ int use_bitmaps; + + if (!remote_refs) { + fprintf(stderr, "No refs in common and none specified; doing nothing.\n" @@ send-pack.c: int send_pack(struct send_pack_args *args, - git_config_get_bool("push.negotiate", &push_negotiate); if (push_negotiate) get_commons_through_negotiation(args->url, remote_refs, &commons); -+ git_config_get_bool("push.usebitmaps", &use_bitmaps); -+ if (use_bitmaps) -+ args->use_bitmaps = 1; ++ if (!git_config_get_bool("push.usebitmaps", &use_bitmaps)) ++ args->use_bitmaps = use_bitmaps; ++ git_config_get_bool("transfer.advertisesid", &advertise_sid); + /* Does the other end support the reporting? */ ## send-pack.h ## @@ send-pack.h: struct send_pack_args { @@ t/t5516-fetch-push.sh: test_expect_success 'push warns or fails when using usern +test_expect_success 'push with config push.useBitmaps' ' + mk_test testrepo heads/main && + git checkout main && -+ GIT_TRACE=1 git push testrepo main:test >/dev/null 2>stderr && -+ grep "no-use-bitmap-index" stderr && ++ GIT_TRACE2_EVENT="$PWD/default" \ ++ git push testrepo main:test && ++ test_subcommand git pack-objects --all-progress-implied --revs --stdout \ ++ --thin --delta-base-offset -q --no-use-bitmap-index /dev/null 2>stderr && -+ ! grep "no-use-bitmap-index" stderr ++ GIT_TRACE2_EVENT="$PWD/true" \ ++ git push testrepo main:test2 && ++ test_subcommand git pack-objects --all-progress-implied --revs --stdout \ ++ --thin --delta-base-offset -q use_bitmaps) + strvec_push(&po.args, "--no-use-bitmap-index"); po.in = -1; po.out = args->stateless_rpc ? -1 : fd; po.git_cmd = 1; @@ -487,6 +489,7 @@ int send_pack(struct send_pack_args *args, struct async demux; const char *push_cert_nonce = NULL; struct packet_reader reader; + int use_bitmaps; if (!remote_refs) { fprintf(stderr, "No refs in common and none specified; doing nothing.\n" @@ -498,6 +501,9 @@ int send_pack(struct send_pack_args *args, if (push_negotiate) get_commons_through_negotiation(args->url, remote_refs, &commons); + if (!git_config_get_bool("push.usebitmaps", &use_bitmaps)) + args->use_bitmaps = use_bitmaps; + git_config_get_bool("transfer.advertisesid", &advertise_sid); /* Does the other end support the reporting? */ diff --git a/send-pack.h b/send-pack.h index e148fcd9609..f7af1b0353e 100644 --- a/send-pack.h +++ b/send-pack.h @@ -26,7 +26,8 @@ struct send_pack_args { /* One of the SEND_PACK_PUSH_CERT_* constants. */ push_cert:2, stateless_rpc:1, - atomic:1; + atomic:1, + use_bitmaps:1; const struct string_list *push_options; }; diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh index dedca106a7a..0d416d1474f 100755 --- a/t/t5516-fetch-push.sh +++ b/t/t5516-fetch-push.sh @@ -1865,4 +1865,25 @@ test_expect_success 'push warns or fails when using username:password' ' test_line_count = 1 warnings ' +test_expect_success 'push with config push.useBitmaps' ' + mk_test testrepo heads/main && + git checkout main && + GIT_TRACE2_EVENT="$PWD/default" \ + git push testrepo main:test && + test_subcommand git pack-objects --all-progress-implied --revs --stdout \ + --thin --delta-base-offset -q --no-use-bitmap-index