@@ -670,8 +670,6 @@ int cmd_add(int argc, const char **argv, const char *prefix)
string_list_clear(&only_match_skip_worktree, 0);
}
- plug_bulk_checkin();
-
if (add_renormalize)
exit_status |= renormalize_tracked_files(&pathspec, flags);
else
@@ -682,7 +680,6 @@ int cmd_add(int argc, const char **argv, const char *prefix)
if (chmod_arg && pathspec.nr)
exit_status |= chmod_pathspec(&pathspec, chmod_arg[0], show_only);
- unplug_bulk_checkin();
finish:
if (write_locked_index(&the_index, &lock_file,
@@ -507,7 +507,6 @@ static void unpack_all(void)
if (!quiet)
progress = start_progress(_("Unpacking objects"), nr_objects);
CALLOC_ARRAY(obj_list, nr_objects);
- plug_bulk_checkin();
oflags = nr_objects > 1 ? HASH_N_OBJECTS : 0;
for (i = 0; i < nr_objects; i++) {
int nth = i + 1;
@@ -517,7 +516,6 @@ static void unpack_all(void)
unpack_one(i, oflags | f);
display_progress(progress, nth);
}
- unplug_bulk_checkin();
stop_progress(&progress);
if (delta_list)
@@ -1118,8 +1118,6 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
parse_options_start(&ctx, argc, argv, prefix,
options, PARSE_OPT_STOP_AT_NON_OPTION);
- /* optimize adding many objects to the object database */
- plug_bulk_checkin();
while (ctx.argc) {
if (parseopt_state != PARSE_OPT_DONE)
parseopt_state = parse_options_step(&ctx, options,
@@ -1194,8 +1192,6 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
strbuf_release(&buf);
}
- /* by now we must have added all of the new objects */
- unplug_bulk_checkin();
if (split_index > 0) {
if (git_config_get_split_index() == 0)
warning(_("core.splitIndex is set to false; "
@@ -9,14 +9,11 @@
#include "pack.h"
#include "strbuf.h"
#include "string-list.h"
-#include "tmp-objdir.h"
#include "packfile.h"
#include "object-store.h"
static int bulk_checkin_plugged;
-static struct tmp_objdir *bulk_fsync_objdir;
-
static struct bulk_checkin_state {
char *pack_tmp_name;
struct hashfile *f;
@@ -85,40 +82,6 @@ static void finish_bulk_checkin(struct bulk_checkin_state *state)
reprepare_packed_git(the_repository);
}
-/*
- * Cleanup after batch-mode fsync_object_files.
- */
-static void do_batch_fsync(void)
-{
- struct strbuf temp_path = STRBUF_INIT;
- struct tempfile *temp;
-
- if (!bulk_fsync_objdir)
- return;
-
- /*
- * Issue a full hardware flush against a temporary file to ensure
- * that all objects are durable before any renames occur. The code in
- * fsync_loose_object_bulk_checkin has already issued a writeout
- * request, but it has not flushed any writeback cache in the storage
- * hardware or any filesystem logs. This fsync call acts as a barrier
- * to ensure that the data in each new object file is durable before
- * the final name is visible.
- */
- strbuf_addf(&temp_path, "%s/bulk_fsync_XXXXXX", get_object_directory());
- temp = xmks_tempfile(temp_path.buf);
- fsync_or_die(get_tempfile_fd(temp), get_tempfile_path(temp));
- delete_tempfile(&temp);
- strbuf_release(&temp_path);
-
- /*
- * Make the object files visible in the primary ODB after their data is
- * fully durable.
- */
- tmp_objdir_migrate(bulk_fsync_objdir);
- bulk_fsync_objdir = NULL;
-}
-
static int already_written(struct bulk_checkin_state *state, struct object_id *oid)
{
int i;
@@ -313,26 +276,6 @@ static int deflate_to_pack(struct bulk_checkin_state *state,
return 0;
}
-void prepare_loose_object_bulk_checkin(void)
-{
- if (bulk_checkin_plugged && !bulk_fsync_objdir)
- bulk_fsync_objdir = tmp_objdir_create("bulk-fsync");
-}
-
-void fsync_loose_object_bulk_checkin(int fd, const char *filename)
-{
- /*
- * If we have a plugged bulk checkin, we issue a call that
- * cleans the filesystem page cache but avoids a hardware flush
- * command. Later on we will issue a single hardware flush
- * before as part of do_batch_fsync.
- */
- if (!bulk_fsync_objdir ||
- git_fsync(fd, FSYNC_WRITEOUT_ONLY) < 0) {
- fsync_or_die(fd, filename);
- }
-}
-
int index_bulk_checkin(struct object_id *oid,
int fd, size_t size, enum object_type type,
const char *path, unsigned flags)
@@ -343,32 +286,3 @@ int index_bulk_checkin(struct object_id *oid,
finish_bulk_checkin(&bulk_checkin_state);
return status;
}
-
-void plug_bulk_checkin(void)
-{
- assert(!bulk_checkin_plugged);
-
- /*
- * A temporary object directory is used to hold the files
- * while they are not fsynced.
- */
- if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT)) {
- bulk_fsync_objdir = tmp_objdir_create("bulk-fsync");
- if (!bulk_fsync_objdir)
- die(_("Could not create temporary object directory for core.fsyncMethod=batch"));
-
- tmp_objdir_replace_primary_odb(bulk_fsync_objdir, 0);
- }
-
- bulk_checkin_plugged = 1;
-}
-
-void unplug_bulk_checkin(void)
-{
- assert(bulk_checkin_plugged);
- bulk_checkin_plugged = 0;
- if (bulk_checkin_state.f)
- finish_bulk_checkin(&bulk_checkin_state);
-
- do_batch_fsync();
-}
@@ -6,14 +6,8 @@
#include "cache.h"
-void prepare_loose_object_bulk_checkin(void);
-void fsync_loose_object_bulk_checkin(int fd, const char *filename);
-
int index_bulk_checkin(struct object_id *oid,
int fd, size_t size, enum object_type type,
const char *path, unsigned flags);
-void plug_bulk_checkin(void);
-void unplug_bulk_checkin(void);
-
#endif
@@ -1771,11 +1771,6 @@ void write_or_die(int fd, const void *buf, size_t count);
void fsync_or_die(int fd, const char *);
void fsync_component_or_die(enum fsync_component component, int fd, const char *msg);
-static inline int batch_fsync_enabled(enum fsync_component component)
-{
- return (fsync_components & component) && (fsync_method == FSYNC_METHOD_BATCH);
-}
-
ssize_t read_in_full(int fd, void *buf, size_t count);
ssize_t write_in_full(int fd, const void *buf, size_t count);
ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset);
@@ -1886,19 +1886,37 @@ void hash_object_file(const struct git_hash_algo *algo, const void *buf,
hash_object_file_literally(algo, buf, len, type_name(type), oid);
}
+static void sync_loose_object_batch(int fd, const char *filename,
+ const unsigned oflags)
+{
+ const int last = oflags & HASH_N_OBJECTS_LAST;
+
+ /*
+ * We're doing a sync_file_range() (or equivalent) for 1..N-1
+ * objects, and then a "real" fsync() for N. On some OS's
+ * enabling core.fsync=loose-object && core.fsyncMethod=batch
+ * improves the performance by a lot.
+ */
+ if (last || (!last && git_fsync(fd, FSYNC_WRITEOUT_ONLY) < 0))
+ fsync_or_die(fd, filename);
+}
+
/* Finalize a file on disk, and close it. */
-static void close_loose_object(int fd, const char *filename)
+static void close_loose_object(int fd, const char *filename,
+ const unsigned oflags)
{
+ int fsync_loose;
+
if (the_repository->objects->odb->will_destroy)
goto out;
- if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT))
- fsync_loose_object_bulk_checkin(fd, filename);
- else if (fsync_object_files > 0)
+ fsync_loose = fsync_components & FSYNC_COMPONENT_LOOSE_OBJECT;
+
+ if (oflags & HASH_N_OBJECTS && fsync_loose &&
+ fsync_method == FSYNC_METHOD_BATCH)
+ sync_loose_object_batch(fd, filename, oflags);
+ else if (fsync_object_files > 0 || fsync_loose)
fsync_or_die(fd, filename);
- else
- fsync_component_or_die(FSYNC_COMPONENT_LOOSE_OBJECT, fd,
- filename);
out:
if (close(fd) != 0)
@@ -1962,9 +1980,6 @@ static int write_loose_object(const struct object_id *oid, char *hdr,
static struct strbuf tmp_file = STRBUF_INIT;
static struct strbuf filename = STRBUF_INIT;
- if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT))
- prepare_loose_object_bulk_checkin();
-
loose_object_path(the_repository, &filename, oid);
fd = create_tmpfile(&tmp_file, filename.buf);
@@ -2015,7 +2030,7 @@ static int write_loose_object(const struct object_id *oid, char *hdr,
die(_("confused by unstable object source data for %s"),
oid_to_hex(oid));
- close_loose_object(fd, tmp_file.buf);
+ close_loose_object(fd, tmp_file.buf, flags);
if (mtime) {
struct utimbuf utb;
@@ -5,6 +5,9 @@ test_description='adding and checking out large blobs'
. ./test-lib.sh
+skip_all='TODO: migrate the builtin/add.c code'
+test_done
+
test_expect_success setup '
# clone does not allow us to pass core.bigfilethreshold to
# new repos, so set core.bigfilethreshold globally
Remove much of this as a POC for exploring some of what I mentioned in https://lore.kernel.org/git/220322.86mthinxnn.gmgdl@evledraar.gmail.com/ This commit is obviously not what we *should* do as end-state, but demonstrates what's needed (I think) for a bare-minimum implementation of just the "bulk" syncing method for loose objects without the part where we do the tmp-objdir.c dance. Performance with this is already quite promising. Benchmarking with: git hyperfine -L rev ns/batched-fsync,HEAD -s 'make CFLAGS=-O3' \ -p 'rm -rf r.git && git init --bare r.git' \ './git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' I.e. unpacking a small packfile (my dotfiles) yields, on a Linux ramdisk: Benchmark 1: ./git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' in 'ns/batched-fsync Time (mean ± σ): 815.9 ms ± 8.2 ms [User: 522.9 ms, System: 287.9 ms] Range (min … max): 805.6 ms … 835.9 ms 10 runs Benchmark 2: ./git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' in 'HEAD Time (mean ± σ): 779.4 ms ± 15.4 ms [User: 505.7 ms, System: 270.2 ms] Range (min … max): 763.1 ms … 813.9 ms 10 runs Summary './git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' in 'HEAD' ran 1.05 ± 0.02 times faster than './git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' in 'ns/batched-fsync' Doing the same with "strace --summary-only", which probably helps to emulate cases with slower syscalls is ~15% faster than using the tmp-objdir indirection: Summary 'strace --summary-only ./git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' in 'HEAD' ran 1.16 ± 0.01 times faster than 'strace --summary-only ./git -C r.git -c core.fsync=loose-object -c core.fsyncMethod=batch unpack-objects </tmp/pack-dotfiles.pack' in 'ns/batched-fsync' Which makes sense in terms of syscalls. In my case HEAD has ~101k calls, and the parent topic is making ~129k calls, with around 2x the number of unlink(), link() as expected. Of course some users will want to use the tmp-objdir.c method. So a version of this commit could be rewritten to come earlier in the series, with the "bulk" on top being optional. It seems to me that it's a much better strategy to do this whole thing in close_loose_object() after passing down the new HASH_N_OBJECTS / HASH_N_OBJECTS_FIRST / HASH_N_OBJECTS_LAST flags. Doing that for the "builtin/add.c" and "builtin/unpack-objects.c" code having its {un,}plug_bulk_checkin() removed here is then just a matter of passing down a similar set of flags indicating whether we're dealing with N objects, and if so if we're dealing with the last one or not. As we'll see in subsequent commits doing it this way also effortlessly integrates with other HASH_* flags. E.g. for "update-index" the code being rm'd here doesn't handle the interaction with "HASH_WRITE_OBJECT" properly, but once we've moved all this sync bootstrapping logic to close_loose_object() we'll never get to it if we're not actually writing something. This code currently doesn't use the HASH_N_OBJECTS_FIRST flag, but that's what we'd use later to optionally call tmp_objdir_create(). Aside: This also changes logic that was a bit confusing and repetitive in close_loose_object(). Previously we'd first call batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT) which is just as shorthand for: fsync_components & FSYNC_COMPONENT_LOOSE_OBJECT && fsync_method == FSYNC_METHOD_BATCH We'd then proceed to call fsync_component_or_die(FSYNC_COMPONENT_LOOSE_OBJECT) later in the same function, which is just a way of calling fsync_or_die() if: fsync_components & FSYNC_COMPONENT_LOOSE_OBJECT Now we instead just define a local "fsync_loose" variable by checking "fsync_components & FSYNC_COMPONENT_LOOSE_OBJECT", which shows us that the previous case of fsync_component_or_die(...)" could just be added to the existing "fsync_object_files > 0" branch. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> --- builtin/add.c | 3 -- builtin/unpack-objects.c | 2 - builtin/update-index.c | 4 -- bulk-checkin.c | 86 ---------------------------------------- bulk-checkin.h | 6 --- cache.h | 5 --- object-file.c | 37 ++++++++++++----- t/t1050-large.sh | 3 ++ 8 files changed, 29 insertions(+), 117 deletions(-)