This is a micro-optimization that grew out of the mailing list discussion
about "strlen()" showing up in profiles.
We used to pass regular C strings around to the low-level tree walking
routines, and while this worked fine, it meant that we needed to call
strlen() on strings that the caller always actually knew the size of
anyway.
So pass the length of the string down wih the string, and avoid
unnecessary calls to strlen(). Also, when extracting a pathname from a
tree entry, use "tree_entry_len()" instead of strlen(), since the length
of the pathname is directly calculable from the decoded tree entry itself
without having to actually do another strlen().
This shaves off another ~5-10% from some loads that are very tree
intensive (notably doing commit filtering by a pathspec).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>"
Signed-off-by: Junio C Hamano <junkio@cox.net>
This means that
git show HEAD:
will now return HEAD^{tree}, which is logically consistent with
git show HEAD:Documentation
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The variable named entry is allocated using malloc() and then
forgotten, it being shadowed by an automatic variable of the
same name. Fixing the array size at 3 worked so far because
the only caller of traverse_trees() needed only as much
entries. Simply remove the shadowing varaible and we're able
to traverse more than three trees and save stack space at the
same time!
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This abstracts away the size of the hash values when copying them
from memory location to memory location, much as the introduction
of hashcmp abstracted away hash value comparsion.
A few call sites were using char* rather than unsigned char* so
I added the cast rather than open hashcpy to be void*. This is a
reasonable tradeoff as most call sites already use unsigned char*
and the existing hashcmp is also declared to be unsigned char*.
[jc: Splitted the patch to "master" part, to be followed by a
patch for merge-recursive.c which is not in "master" yet.
Fixed the cast in the latter hunk to combine-diff.c which was
wrong in the original.
Also converted ones left-over in combine-diff.c, diff-lib.c and
upload-pack.c ]
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
ANSI C99 doesn't allow void-pointer arithmetic. This patch fixes this in
various ways. Usually the strategy that required the least changes was used.
Signed-off-by: Florian Forster <octo@verplant.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This adds a "tree_entry()" function that combines the common operation of
doing a "tree_entry_extract()" + "update_tree_entry()".
It also has a simplified calling convention, designed for simple loops
that traverse over a whole tree: the arguments are pointers to the tree
descriptor and a name_entry structure to fill in, and it returns a boolean
"true" if there was an entry left to be gotten in the tree.
This allows tree traversal with
struct tree_desc desc;
struct name_entry entry;
desc.buf = tree->buffer;
desc.size = tree->size;
while (tree_entry(&desc, &entry) {
... use "entry.{path, sha1, mode, pathlen}" ...
}
which is not only shorter than writing it out in full, it's hopefully less
error prone too.
[ It's actually a tad faster too - we don't need to recalculate the entry
pathlength in both extract and update, but need to do it only once.
Also, some callers can avoid doing a "strlen()" on the result, since
it's returned as part of the name_entry structure.
However, by now we're talking just 1% speedup on "git-rev-list --objects
--all", and we're definitely at the point where tree walking is no
longer the issue any more. ]
NOTE! Not everybody wants to use this new helper function, since some of
the tree walkers very much on purpose do the descriptor update separately
from the entry extraction. So the "extract + update" sequence still
remains as the core sequence, this is just a simplified interface.
We should probably add a silly two-line inline helper function for
initializing the descriptor from the "struct tree" too, just to cut down
on the noise from that common "desc" initializer.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Doing an oprofile run on the result of my git rev-list memory leak fixes
and tree parsing cleanups, I was surprised by the third-highest entry
being
samples % image name app name symbol name
179751 2.7163 libc-2.4.so libc-2.4.so _IO_vfscanf@@GLIBC_2.4
where that 2.7% is actually more than 5% of one CPU, because this was run
on a dual CPU setup with the other CPU just being idle.
That seems to all be from the use of 'sscanf(tree, "%o", &mode)' for the
tree buffer parsing.
So do the trivial octal parsing by hand, which also gives us where the
first space in the string is (and thus where the pathname starts) so we
can get rid of the "strchr(tree, ' ')" call too.
This brings the "git rev-list --all --objects" time down from 63 seconds
to 55 seconds on the historical kernel archive for me, so it's quite
noticeable - tree parsing is a lot of what we end up doing when following
all the objects.
[ I also see a 5% speedup on a full "git fsck-objects" on the current
kernel archive, so that sscanf() really does seem to have hurt our
performance by a surprising amount ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This replaces occurences of "blob", "commit", "tag", and "tree",
where they're really used as type specifiers, which we already
have defined global constants for.
Signed-off-by: Peter Eriksen <s022018@student.dtu.dk>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Introduce tree-walk.[ch] and move "struct tree_desc" and
associated functions from various places.
Rename DIFF_FILE_CANON_MODE(mode) macro to canon_mode(mode) and
move it to cache.h. This macro returns the canonicalized
st_mode value in the host byte order for files, symlinks and
directories -- to be compared with a tree_desc entry.
create_ce_mode(mode) in cache.h is similar but is intended to be
used for index entries (so it does not work for directories) and
returns the value in the network byte order.
Signed-off-by: Junio C Hamano <junkio@cox.net>
