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Improve git-status performance for v1.8.5 #107
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Commit 5fee995 introduced the stage_updated_gitmodules() function to add submodule configuration updates to the index. It assumed that even after calling remove_cache_entry_at() the same cache entry would still be valid. This was true in the old days, as cache entries could never be freed, but that is not so sure in the present as there is ongoing work to free removed cache entries, which makes this code segfault. Fix that by calling add_file_to_cache() instead of open coding it. Also remove the "could not find .gitmodules in index" warning, as that won't happen in regular use cases (and by then just silently adding it to the index we do the right thing). Thanks-to: Karsten Blees <karsten.blees@gmail.com> Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The existing hashtable implementation (in hash.[ch]) uses open addressing (i.e. resolve hash collisions by distributing entries across the table). Thus, removal is difficult to implement with less than O(n) complexity. Resolving collisions of entries with identical hashes (e.g. via chaining) is left to the client code. Add a hashtable implementation that supports O(1) removal and is slightly easier to use due to builtin entry chaining. Supports all basic operations init, free, get, add, remove and iteration. Also includes ready-to-use hash functions based on the public domain FNV-1 algorithm (http://www.isthe.com/chongo/tech/comp/fnv). The per-entry data structure (hashmap_entry) is piggybacked in front of the client's data structure to save memory. See test-hashmap.c for usage examples. The hashtable is resized by a factor of four when 80% full. With these settings, average memory consumption is about 2/3 of hash.[ch], and insertion is about twice as fast due to less frequent resizing. Lookups are also slightly faster, because entries are strictly confined to their bucket (i.e. no data of other buckets needs to be traversed). Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Karsten Blees <blees@dcon.de>
Move opendir down in preparation for the next patch. Signed-off-by: Karsten Blees <blees@dcon.de>
Emulating the POSIX dirent API on Windows via FindFirstFile/FindNextFile is pretty staightforward, however, most of the information provided in the WIN32_FIND_DATA structure is thrown away in the process. A more sophisticated implementation may cache this data, e.g. for later reuse in calls to lstat. Make the dirent implementation pluggable so that it can be switched at runtime, e.g. based on a config option. Define a base DIR structure with pointers to readdir/closedir that match the opendir implementation (i.e. similar to vtable pointers in OOP). Define readdir/closedir so that they call the function pointers in the DIR structure. This allows to choose the opendir implementation on a call-by-call basis. Move the fixed sized dirent.d_name buffer to the dirent-specific DIR structure, as d_name may be implementation specific (e.g. a caching implementation may just set d_name to point into the cache instead of copying the entire file name string). Signed-off-by: Karsten Blees <blees@dcon.de>
Emulating the POSIX lstat API on Windows via GetFileAttributes[Ex] is quite slow. Windows operating system APIs seem to be much better at scanning the status of entire directories than checking single files. A caching implementation may improve performance by bulk-reading entire directories or reusing data obtained via opendir / readdir. Make the lstat implementation pluggable so that it can be switched at runtime, e.g. based on a config option. Signed-off-by: Karsten Blees <blees@dcon.de>
Add a macro to mark code sections that only read from the file system, along with a config option and documentation. This facilitates implementation of relatively simple file system level caches without the need to synchronize with the file system. Enable read-only sections for 'git status' and preload_index. Signed-off-by: Karsten Blees <blees@dcon.de>
Checking the work tree status is quite slow on Windows, due to slow lstat emulation (git calls lstat once for each file in the index). Windows operating system APIs seem to be much better at scanning the status of entire directories than checking single files. Add an lstat implementation that uses a cache for lstat data. Cache misses read the entire parent directory and add it to the cache. Subsequent lstat calls for the same directory are served directly from the cache. Also implement opendir / readdir / closedir so that they create and use directory listings in the cache. The cache doesn't track file system changes and doesn't plug into any modifying file APIs, so it has to be explicitly enabled for git functions that don't modify the working copy. Note: in an earlier version of this patch, the cache was always active and tracked file system changes via ReadDirectoryChangesW. However, this was much more complex and had negative impact on the performance of modifying git commands such as 'git checkout'. Signed-off-by: Karsten Blees <blees@dcon.de>
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MSysGit - the development behind Git for Windows » git #144 SUCCESS |
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I merged it directly into 'master'. |
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Followup to #94