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Revision 9dd5245c1043dd18fd7b3f44b9e51eef7e4b58d8 authored by Jeff King on 02 February 2012, 08:24:28 UTC, committed by Junio C Hamano on 02 February 2012, 18:36:08 UTC 
grep: pre-load userdiff drivers when threaded
 
The low-level grep_source code will automatically load the
userdiff driver to see whether a file is binary. However,
when we are threaded, it will load the drivers in a
non-deterministic order, handling each one as its assigned
thread happens to be scheduled.

Meanwhile, the attribute lookup code (which underlies the
userdiff driver lookup) is optimized to handle paths in
sequential order (because they tend to share the same
gitattributes files). Multi-threading the lookups destroys
the locality and makes this optimization less effective.

We can fix this by pre-loading the userdiff driver in the
main thread, before we hand off the file to a worker thread.
My best-of-five for "git grep foo" on the linux-2.6
repository went from:

  real    0m0.391s
  user    0m1.708s
  sys     0m0.584s

to:

  real    0m0.360s
  user    0m1.576s
  sys     0m0.572s

Not a huge speedup, but it's quite easy to do. The only
trick is that we shouldn't perform this optimization if "-a"
was used, in which case we won't bother checking whether
the files are binary at all.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 0826579
Raw File
fsck.h 
#ifndef GIT_FSCK_H
#define GIT_FSCK_H

#define FSCK_ERROR 1
#define FSCK_WARN 2

/*
 * callback function for fsck_walk
 * type is the expected type of the object or OBJ_ANY
 * the return value is:
 *     0	everything OK
 *     <0	error signaled and abort
 *     >0	error signaled and do not abort
 */
typedef int (*fsck_walk_func)(struct object *obj, int type, void *data);

/* callback for fsck_object, type is FSCK_ERROR or FSCK_WARN */
typedef int (*fsck_error)(struct object *obj, int type, const char *err, ...);

__attribute__((format (printf, 3, 4)))
int fsck_error_function(struct object *obj, int type, const char *fmt, ...);

/* descend in all linked child objects
 * the return value is:
 *    -1	error in processing the object
 *    <0	return value of the callback, which lead to an abort
 *    >0	return value of the first signaled error >0 (in the case of no other errors)
 *    0		everything OK
 */
int fsck_walk(struct object *obj, fsck_walk_func walk, void *data);
int fsck_object(struct object *obj, int strict, fsck_error error_func);

#endif
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