Commit notes are blobs which are shown together with the commit
message. These blobs are taken from the notes ref, which you can
configure by the config variable core.notesRef, which in turn can
be overridden by the environment variable GIT_NOTES_REF.
The notes ref is a branch which contains "files" whose names are
the names of the corresponding commits (i.e. the SHA-1).
The rationale for putting this information into a ref is this: we
want to be able to fetch and possibly union-merge the notes,
maybe even look at the date when a note was introduced, and we
want to store them efficiently together with the other objects.
This patch has been improved by the following contributions:
- Thomas Rast: fix core.notesRef documentation
- Tor Arne Vestbø: fix printing of multi-line notes
- Alex Riesen: Using char array instead of char pointer costs less BSS
- Johan Herland: Plug leak when msg is good, but msglen or type causes return
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Tor Arne Vestbø <tavestbo@trolltech.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
get_commit_notes(): Plug memory leak when 'if' triggers, but not because of read_sha1_file() failure
Previously the old error message just told the user that it was not
possible to delete the ref from the packed-refs file. Give instructions
on how to resolve the problem.
Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
A local clone without hardlinks copies all objects, including dangling
ones, to the new repository. Since the mtimes are renewed, those
dangling objects cannot be pruned by "git gc --prune", even if they
would have been old enough for pruning in the original repository.
Instead, preserve mtime during copy. "git gc --prune" will then work
in the clone just like it did in the original.
Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 2d14d65 (Use a clearer style to issue commands to remote helpers,
2009-09-03) I happened to notice two changes like this:
- write_in_full(helper->in, "list\n", 5);
+
+ strbuf_addstr(&buf, "list\n");
+ write_in_full(helper->in, buf.buf, buf.len);
+ strbuf_reset(&buf);
IMHO, it would be better to define a new function,
static inline ssize_t write_str_in_full(int fd, const char *str)
{
return write_in_full(fd, str, strlen(str));
}
and then use it like this:
- strbuf_addstr(&buf, "list\n");
- write_in_full(helper->in, buf.buf, buf.len);
- strbuf_reset(&buf);
+ write_str_in_full(helper->in, "list\n");
Thus not requiring the added allocation, and still avoiding
the maintenance risk of literal string lengths.
These days, compilers are good enough that strlen("literal")
imposes no run-time cost.
Transformed via this:
perl -pi -e \
's/write_in_full\((.*?), (".*?"), \d+\)/write_str_in_full($1, $2)/'\
$(git grep -l 'write_in_full.*"')
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This message is designed to help new users understand what
has happened when refs fail to push. However, it does not
help experienced users at all, and significantly clutters
the output, frequently dwarfing the regular status table and
making it harder to see.
This patch introduces a general configuration mechanism for
optional messages, with this push message as the first
example.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* lt/approxidate:
fix approxidate parsing of relative months and years
tests: add date printing and parsing tests
refactor test-date interface
Add date formatting and parsing functions relative to a given time
Further 'approxidate' improvements
Improve on 'approxidate'
Conflicts:
date.c
The main purpose is to allow predictable testing of the code.
Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git reset without argument displays a summary of the local modification,
like this:
$ git reset
Makefile: locally modified
Some people have problems with this; they look like an error message.
This patch makes its output mimic how "git checkout $another_branch"
reports the paths with local modifications. "git add --refresh --verbose"
is changed in the same way.
It also adds a header to make it clear that the output is informative,
and not an error.
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
The change in the output is going to become more general than just saying
"changed", so let's make the variable name more general too.
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* cc/replace:
t6050: check pushing something based on a replaced commit
Documentation: add documentation for "git replace"
Add git-replace to .gitignore
builtin-replace: use "usage_msg_opt" to give better error messages
parse-options: add new function "usage_msg_opt"
builtin-replace: teach "git replace" to actually replace
Add new "git replace" command
environment: add global variable to disable replacement
mktag: call "check_sha1_signature" with the replacement sha1
replace_object: add a test case
object: call "check_sha1_signature" with the replacement sha1
sha1_file: add a "read_sha1_file_repl" function
replace_object: add mechanism to replace objects found in "refs/replace/"
refs: add a "for_each_replace_ref" function
Merlyn noticed that Documentation/install-doc-quick.sh no longer correctly
removes old installed documents when the target directory has a leading
path that is a symlink. It turns out that "checkout-index --prefix" was
broken by recent b6986d8 (git-checkout: be careful about untracked
symlinks, 2009-07-29).
I suspect has_symlink_leading_path() could learn the third parameter
(prefix that is allowed to be symlinked directories) to allow us to retire
a similar function has_dirs_only_path().
Another avenue of fixing this I considered was to get rid of base_dir and
base_dir_len from "struct checkout", and instead make "git checkout-index"
when run with --prefix mkdir the leading path and chdir in there. It
might be the best longer term solution to this issue, as the base_dir
feature is used only by that rather obscure codepath as far as I know.
But at least this patch should fix this breakage.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce --ignore-whitespace option and corresponding config bool to
ignore whitespace differences while applying patches, akin to the
'patch' program.
'git am', 'git rebase' and the bash git completion are made aware of
this option.
Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This fixes the case where an untracked symlink that points at a directory
with tracked paths confuses the checkout logic, demostrated in t6035.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* js/maint-graft-unhide-true-parents:
git repack: keep commits hidden by a graft
Add a test showing that 'git repack' throws away grafted-away parents
Conflicts:
git-repack.sh
When you have grafts that pretend that a given commit has different
parents than the ones recorded in the commit object, it is dangerous
to let 'git repack' remove those hidden parents, as you can easily
remove the graft and end up with a broken repository.
So let's play it safe and keep those parent objects and everything
that is reachable by them, in addition to the grafted parents.
As this behavior can only be triggered by git pack-objects, and as that
command handles duplicate parents gracefully, we do not bother to cull
duplicated parents that may result by using both true and grafted
parents.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the message said "we will be changing the default in the future, so
this is to warn people who want to keep the current default what to do",
it would have made some sense, but as it stands, the message is merely an
unsolicited advertisement for a new feature, which it is not helpful at
all. Squelch it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The threaded index preloading will want it, so that it can avoid
locking by simply using a per-thread symlink/directory cache.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Naturally, prep_temp_blob() did not care about filenames.
As a result, GIT_EXTERNAL_DIFF and textconv generated
filenames such as ".diff_XXXXXX".
This modifies prep_temp_blob() to generate user-friendly
filenames when creating temporary files.
Diffing "name.ext" now generates "XXXXXX_name.ext".
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new "read_replace_refs" global variable is set to 1 by
default, so that replace refs are used by default. But
reachability traversal and packing commands ("cmd_fsck",
"cmd_prune", "cmd_pack_objects", "upload_pack",
"cmd_unpack_objects") set it to 0, as they must work with the
original DAG.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new function will replace "read_sha1_file". This latter function
becoming just a stub to call the former will a NULL "replacement"
argument.
This new function is needed because sometimes we need to use the
replacement sha1.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Essentially; s/type* /type */ as per the coding guidelines.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"Unreliable hardlinks" is a misleading description for what is happening.
So rename it to something less misleading.
Suggested by Linus Torvalds.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It seems that accessing NTFS partitions with ufsd (at least on my EeePC)
has an unnerving bug: if you link() a file and unlink() it right away,
the target of the link() will have the correct size, but consist of NULs.
It seems as if the calls are simply not serialized correctly, as single-stepping
through the function move_temp_to_file() works flawlessly.
As ufsd is "Commertial software" (sic!), I cannot fix it, and have to work
around it in Git.
At the same time, it seems that this fixes msysGit issues 222 and 229 to
assume that Windows cannot handle link() && unlink().
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/name-branch:
Don't permit ref/branch names to end with ".lock"
check_ref_format(): tighten refname rules
strbuf_check_branch_ref(): a helper to check a refname for a branch
Fix branch -m @{-1} newname
check-ref-format --branch: give Porcelain a way to grok branch shorthand
strbuf_branchname(): a wrapper for branch name shorthands
Rename interpret/substitute nth_last_branch functions
Conflicts:
Documentation/git-check-ref-format.txt
* jc/shared-literally:
t1301: loosen test for forced modes
set_shared_perm(): sometimes we know what the final mode bits should look like
move_temp_to_file(): do not forget to chmod() in "Coda hack" codepath
Move chmod(foo, 0444) into move_temp_to_file()
"core.sharedrepository = 0mode" should set, not loosen
* jc/maint-1.6.0-keep-pack:
pack-objects: don't loosen objects available in alternate or kept packs
t7700: demonstrate repack flaw which may loosen objects unnecessarily
Remove --kept-pack-only option and associated infrastructure
pack-objects: only repack or loosen objects residing in "local" packs
git-repack.sh: don't use --kept-pack-only option to pack-objects
t7700-repack: add two new tests demonstrating repacking flaws
Conflicts:
t/t7700-repack.sh
adjust_shared_perm() first obtains the mode bits from lstat(2), expecting
to find what the result of applying user's umask is, and then tweaks it
as necessary. When the file to be adjusted is created with mkstemp(3),
however, the mode thusly obtained does not have anything to do with user's
umask, and we would need to start from 0444 in such a case and there is no
point running lstat(2) for such a path.
This introduces a new API set_shared_perm() to bypass the lstat(2) and
instead force setting the mode bits to the desired value directly.
adjust_shared_perm() becomes a thin wrapper to the function.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* fg/push-default:
builtin-push.c: Fix typo: "anythig" -> "anything"
Display warning for default git push with no push.default config
New config push.default to decide default behavior for push
Conflicts:
Documentation/config.txt
These allow you to say "git checkout @{-2}" to switch to the branch two
"branch switching" ago by pretending as if you typed the name of that
branch. As it is likely that we will be introducing more short-hands to
write the name of a branch without writing it explicitly, rename the
functions from "nth_last_branch" to more generic "branch_name", to prepare
for different semantics.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This option to pack-objects/rev-list was created to improve the -A and -a
options of repack. It was found to be lacking in that it did not provide
the ability to differentiate between local and non-local kept packs, and
found to be unnecessary since objects residing in local kept packs can be
filtered out by the --honor-pack-keep option.
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* js/remote-improvements: (23 commits)
builtin-remote.c: no "commented out" code, please
builtin-remote: new show output style for push refspecs
builtin-remote: new show output style
remote: make guess_remote_head() use exact HEAD lookup if it is available
builtin-remote: add set-head subcommand
builtin-remote: teach show to display remote HEAD
builtin-remote: fix two inconsistencies in the output of "show <remote>"
builtin-remote: make get_remote_ref_states() always populate states.tracked
builtin-remote: rename variables and eliminate redundant function call
builtin-remote: remove unused code in get_ref_states
builtin-remote: refactor duplicated cleanup code
string-list: new for_each_string_list() function
remote: make match_refs() not short-circuit
remote: make match_refs() copy src ref before assigning to peer_ref
remote: let guess_remote_head() optionally return all matches
remote: make copy_ref() perform a deep copy
remote: simplify guess_remote_head()
move locate_head() to remote.c
move duplicated ref_newer() to remote.c
move duplicated get_local_heads() to remote.c
...
Conflicts:
builtin-clone.c
* kb/checkout-optim:
Revert "lstat_cache(): print a warning if doing ping-pong between cache types"
checkout bugfix: use stat.mtime instead of stat.ctime in two places
Makefile: Set compiler switch for USE_NSEC
Create USE_ST_TIMESPEC and turn it on for Darwin
Not all systems use st_[cm]tim field for ns resolution file timestamp
Record ns-timestamps if possible, but do not use it without USE_NSEC
write_index(): update index_state->timestamp after flushing to disk
verify_uptodate(): add ce_uptodate(ce) test
make USE_NSEC work as expected
fix compile error when USE_NSEC is defined
check_updates(): effective removal of cache entries marked CE_REMOVE
lstat_cache(): print a warning if doing ping-pong between cache types
show_patch_diff(): remove a call to fstat()
write_entry(): use fstat() instead of lstat() when file is open
write_entry(): cleanup of some duplicated code
create_directories(): remove some memcpy() and strchr() calls
unlink_entry(): introduce schedule_dir_for_removal()
lstat_cache(): swap func(length, string) into func(string, length)
lstat_cache(): generalise longest_match_lstat_cache()
lstat_cache(): small cleanup and optimisation
When "git push" is not told what refspecs to push, it pushes all matching
branches to the current remote. For some workflows this default is not
useful, and surprises new users. Some have even found that this default
behaviour is too easy to trigger by accident with unwanted consequences.
Introduce a new configuration variable "push.default" that decides what
action git push should take if no refspecs are given or implied by the
command line arguments or the current remote configuration.
Possible values are:
'nothing' : Push nothing;
'matching' : Current default behaviour, push all branches that already
exist in the current remote;
'tracking' : Push the current branch to whatever it is tracking;
'current' : Push the current branch to a branch of the same name,
i.e. HEAD.
Signed-off-by: Finn Arne Gangstad <finnag@pvv.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/maint-1.6.0-keep-pack:
is_kept_pack(): final clean-up
Simplify is_kept_pack()
Consolidate ignore_packed logic more
has_sha1_kept_pack(): take "struct rev_info"
has_sha1_pack(): refactor "pretend these packs do not exist" interface
git-repack: resist stray environment variable
Now is_kept_pack() is just a member lookup into a structure, we can write
it as such.
Also rewrite the sole caller of has_sha1_kept_pack() to switch on the
criteria the callee uses (namely, revs->kept_pack_only) between calling
has_sha1_kept_pack() and has_sha1_pack(), so that these two callees do not
have to take a pointer to struct rev_info as an argument.
This removes the header file dependency issue temporarily introduced by
the earlier commit, so we revert changes associated to that as well.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This refactors three loops that check if a given packfile is on the
ignore_packed list into a function is_kept_pack(). The function returns
false for a pack on the list, and true for a pack not on the list, because
this list is solely used by "git repack" to pass list of packfiles that do
not have corresponding .keep files, i.e. a packfile not on the list is
"kept".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Its "ignore_packed" parameter always comes from struct rev_info. This
patch makes the function take a pointer to the surrounding structure, so
that the refactoring in the next patch becomes easier to review.
There is an unfortunate header file dependency and the easiest workaround
is to temporarily move the function declaration from cache.h to
revision.h; this will be moved back to cache.h once the function loses
this "ignore_packed" parameter altogether in the later part of the
series.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of the callers of this function except only one pass NULL to its last
parameter, ignore_packed.
Introduce has_sha1_kept_pack() function that has the function signature
and the semantics of this function, and convert the sole caller that does
not pass NULL to call this new function.
All other callers and has_sha1_pack() lose the ignore_packed parameter.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since it doesn't actually touch its argument, this makes
sense.
However, we still want to return a non-const version (which
requires a cast) so that this:
struct ref *a, *b;
a = find_ref_by_name(b);
works. Unfortunately, you can also silently strip the const
from a variable:
struct ref *a;
const struct ref *b;
a = find_ref_by_name(b);
This is a classic C const problem because there is no way to
say "return the type with the same constness that was passed
to us"; we provide the same semantics as standard library
functions like strchr.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this timestamp is used to check for racy-clean files, it is
important to keep it uptodate.
For the 'git checkout' command without the '-q' option, this make a
huge difference. Before, each and every file which was updated, was
racy-clean after the call to unpack_trees() and write_index() but
before the GIT process ended.
And because of the call to show_local_changes() in builtin-checkout.c,
we ended up reading those files back into memory, doing a SHA1 to
check if the files was really different from the index. And, of
course, no file was different.
With this fix, 'git checkout' without the '-q' option should now be
almost as fast as with the '-q' option, but not quite, as we still do
some few lstat(2) calls more without the '-q' option.
Below is some average numbers for 10 checkout's to v2.6.27 and 10 to
v2.6.25 of the Linux kernel, to show the difference:
before (git version 1.6.2.rc1.256.g58a87):
7.860 user 2.427 sys 19.465 real 52.8% CPU faults: 0 major 95331 minor
after:
6.184 user 2.160 sys 17.619 real 47.4% CPU faults: 0 major 38994 minor
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Talking about --date, one thing I wanted for the 1234567890 date was to
get things in the raw format. Sure, you get them with --pretty=raw, but it
felt a bit sad that you couldn't just ask for the date in raw format.
So here's a throw-away patch (meaning: I won't be re-sending it, because I
really don't think it's a big deal) to add "--date=raw". It just prints
out the internal raw git format - seconds since epoch plus timezone (put
another way: 'date +"%s %z"' format)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just saying that index.lock exists doesn't tell the user _what_ to do
to fix the problem. We should give an indication that it's normally
safe to delete index.lock after making sure git isn't running here.
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function strip_path_suffix() will try to strip a given suffix from
a given path. The suffix must start at a directory boundary (i.e. "core"
is not a path suffix of "libexec/git-core", but "git-core" is).
Arbitrary runs of directory separators ("slashes") are assumed identical.
Example:
strip_path_suffix("C:\\msysgit/\\libexec\\git-core",
"libexec///git-core", &prefix)
will set prefix to "C:\\msysgit" and return 0.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since the filesystem ext4 is now defined as stable in Linux v2.6.28,
and ext4 supports nanonsecond resolution timestamps natively, it is
time to make USE_NSEC work as expected.
This will make racy git situations less likely to happen. For 'git
checkout' this means it will be less likely that we have to open, read
the contents of the file into RAM, and check if file is really
modified or not. The result sould be a litle less used CPU time, less
pagefaults and a litle faster program, at least for 'git checkout'.
Since the number of possible racy git situations would increase when
disks gets faster, this patch would be more and more helpfull as times
go by. For a fast Solid State Disk, this patch should be helpfull.
Note that, when file operations starts to take less than 1 nanosecond,
one would again start to get more racy git situations.
For more info on racy git, see Documentation/technical/racy-git.txt
For more info on ext4, see http://kernelnewbies.org/Ext4
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Below is oprofile output from GIT command 'git chekcout -q my-v2.6.25'
(move from tag v2.6.27 to tag v2.6.25 of the Linux kernel):
CPU: Core 2, speed 1999.95 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit
mask of 0x00 (Unhalted core cycles) count 20000
Counted INST_RETIRED_ANY_P events (number of instructions retired) with a
unit mask of 0x00 (No unit mask) count 20000
CPU_CLK_UNHALT...|INST_RETIRED:2...|
samples| %| samples| %|
------------------------------------
409247 100.000 342878 100.000 git
CPU_CLK_UNHALT...|INST_RETIRED:2...|
samples| %| samples| %|
------------------------------------
260476 63.6476 257843 75.1996 libz.so.1.2.3
100876 24.6492 64378 18.7758 kernel-2.6.28.4_2.vmlinux
30850 7.5382 7874 2.2964 libc-2.9.so
14775 3.6103 8390 2.4469 git
2020 0.4936 4325 1.2614 libcrypto.so.0.9.8
191 0.0467 32 0.0093 libpthread-2.9.so
58 0.0142 36 0.0105 ld-2.9.so
1 2.4e-04 0 0 libldap-2.3.so.0.2.31
Detail list of the top 20 function entries (libz counted in one blob):
CPU_CLK_UNHALTED INST_RETIRED_ANY_P
samples % samples % image name symbol name
260476 63.6862 257843 75.2725 libz.so.1.2.3 /lib/libz.so.1.2.3
16587 4.0555 3636 1.0615 libc-2.9.so memcpy
7710 1.8851 277 0.0809 libc-2.9.so memmove
3679 0.8995 1108 0.3235 kernel-2.6.28.4_2.vmlinux d_validate
3546 0.8670 2607 0.7611 kernel-2.6.28.4_2.vmlinux __getblk
3174 0.7760 1813 0.5293 libc-2.9.so _int_malloc
2396 0.5858 3681 1.0746 kernel-2.6.28.4_2.vmlinux copy_to_user
2270 0.5550 2528 0.7380 kernel-2.6.28.4_2.vmlinux __link_path_walk
2205 0.5391 1797 0.5246 kernel-2.6.28.4_2.vmlinux ext4_mark_iloc_dirty
2103 0.5142 1203 0.3512 kernel-2.6.28.4_2.vmlinux find_first_zero_bit
2077 0.5078 997 0.2911 kernel-2.6.28.4_2.vmlinux do_get_write_access
2070 0.5061 514 0.1501 git cache_name_compare
2043 0.4995 1501 0.4382 kernel-2.6.28.4_2.vmlinux rcu_irq_exit
2022 0.4944 1732 0.5056 kernel-2.6.28.4_2.vmlinux __ext4_get_inode_loc
2020 0.4939 4325 1.2626 libcrypto.so.0.9.8 /usr/lib/libcrypto.so.0.9.8
1965 0.4804 1384 0.4040 git patch_delta
1708 0.4176 984 0.2873 kernel-2.6.28.4_2.vmlinux rcu_sched_grace_period
1682 0.4112 727 0.2122 kernel-2.6.28.4_2.vmlinux sysfs_slab_alias
1659 0.4056 290 0.0847 git find_pack_entry_one
1480 0.3619 1307 0.3816 kernel-2.6.28.4_2.vmlinux ext4_writepage_trans_blocks
Notice the memmove line, where the CPU did 7710 / 277 = 27.8 cycles
per instruction, and compared to the total cycles spent inside the
source code of GIT for this command, all the memmove() calls
translates to (7710 * 100) / 14775 = 52.2% of this.
Retesting with a GIT program compiled for gcov usage, I found out that
the memmove() calls came from remove_index_entry_at() in read-cache.c,
where we have:
memmove(istate->cache + pos,
istate->cache + pos + 1,
(istate->cache_nr - pos) * sizeof(struct cache_entry *));
remove_index_entry_at() is called 4902 times from check_updates() in
unpack-trees.c, and each time called we move each cache_entry pointers
(from the removed one) one step to the left.
Since we have 28828 entries in the cache this time, and if we on
average move half of them each time, we in total move approximately
4902 * 0.5 * 28828 * 4 = 282 629 712 bytes, or twice this amount if
each pointer is 8 bytes (64 bit).
OK, is seems that the function check_updates() is called 28 times, so
the estimated guess above had been more correct if check_updates() had
been called only once, but the point is: we get lots of bytes moved.
To fix this, and use an O(N) algorithm instead, where N is the number
of cache_entries, we delete/remove all entries in one loop through all
entries.
From a retest, the new remove_marked_cache_entries() from the patch
below, ended up with the following output line from oprofile:
46 0.0105 15 0.0041 git remove_marked_cache_entries
If we can trust the numbers from oprofile in this case, we saved
approximately ((7710 - 46) * 20000) / (2 * 1000 * 1000 * 1000) = 0.077
seconds CPU time with this fix for this particular test. And notice
that now the CPU did only 46 / 15 = 3.1 cycles/instruction.
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
