The threading model for fscache has been to have a single, global cache.
This puts requirements on it to be thread safe so that callers like
preload-index can call it from multiple threads. This was implemented
with a single mutex and completion events which introduces contention
between the calling threads.
Simplify the threading model by making fscache thread specific. This allows
us to remove the global mutex and synchronization events entirely and instead
associate a fscache with every thread that requests one. This works well with
the current multi-threading which divides the cache entries into blocks with
a separate thread processing each block.
At the end of each worker thread, if there is a fscache on the primary
thread, merge the cached results from the worker into the primary thread
cache. This enables us to reuse the cache later especially when scanning for
untracked files.
In testing, this reduced the time spent in preload_index() by about 25% and
also reduced the CPU utilization significantly. On a repo with ~200K files,
it reduced overall status times by ~12%.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Make fscache_enabled() function public rather than static.
Remove unneeded fscache_is_enabled() function.
Change is_fscache_enabled() macro to call fscache_enabled().
is_fscache_enabled() now takes a pathname so that the answer
is more precise and mean "is fscache enabled for this pathname",
since fscache only stores repo-relative paths and not absolute
paths, we can avoid attempting lookups for absolute paths.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Update enable_fscache() to take an optional initial size parameter which is
used to initialize the hashmap so that it can avoid having to rehash as
additional entries are added.
Add a separate disable_fscache() macro to make the code clearer and easier
to read.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Teach read_directory_recursive() and add_excludes() to
be aware of optional fscache and avoid trying to open()
and fstat() non-existant ".gitignore" files in every
directory in the worktree.
The current code in add_excludes() calls open() and then
fstat() for a ".gitignore" file in each directory present
in the worktree. Change that when fscache is enabled to
call lstat() first and if present, call open().
This seems backwards because both lstat needs to do more
work than fstat. But when fscache is enabled, fscache will
already know if the .gitignore file exists and can completely
avoid the IO calls. This works because of the lstat diversion
to mingw_lstat when fscache is enabled.
This reduced status times on a 350K file enlistment of the
Windows repo on a NVMe SSD by 0.25 seconds.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Add tracing around initializing and discarding mempools. In discard report
on the amount of memory unused in the current block to help tune setting
the initial_size.
Signed-off-by: Ben Peart <benpeart@microsoft.com>
If multiple threads access a directory that is not yet in the cache, the
directory will be loaded by each thread. Only one of the results is added
to the cache, all others are leaked. This wastes performance and memory.
On cache miss, add a future object to the cache to indicate that the
directory is currently being loaded. Subsequent threads register themselves
with the future object and wait. When the first thread has loaded the
directory, it replaces the future object with the result and notifies
waiting threads.
Signed-off-by: Karsten Blees <blees@dcon.de>
Teach FSCACHE to remember "not found" directories.
This is a performance optimization.
FSCACHE is a performance optimization available for Windows. It
intercepts Posix-style lstat() calls into an in-memory directory
using FindFirst/FindNext. It improves performance on Windows by
catching the first lstat() call in a directory, using FindFirst/
FindNext to read the list of files (and attribute data) for the
entire directory into the cache, and short-cut subsequent lstat()
calls in the same directory. This gives a major performance
boost on Windows.
However, it does not remember "not found" directories. When STATUS
runs and there are missing directories, the lstat() interception
fails to find the parent directory and simply return ENOENT for the
file -- it does not remember that the FindFirst on the directory
failed. Thus subsequent lstat() calls in the same directory, each
re-attempt the FindFirst. This completely defeats any performance
gains.
This can be seen by doing a sparse-checkout on a large repo and
then doing a read-tree to reset the skip-worktree bits and then
running status.
This change reduced status times for my very large repo by 60%.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.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>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.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>
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>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.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 (similar to vtable pointers in
Object-Oriented Programming). 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.
Make the fixed-size `dirent.d_name` buffer a flex array, as `d_name` may
be implementation specific (e.g. a caching implementation may allocate a
`struct dirent` with _just_ the size needed to hold the `d_name` in
question).
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
We will use them in the upcoming "FSCache" patches (to accelerate
sequential lstat() calls).
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
These changes are necessary to support better Git for Windows' new
auto-update feature.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When using remotes (with git-flow especially), the remote reference names
are almost always wordwrapped in the "list references" window because it's
somewhat narrow by default. It's possible to resize it with a mouse,
but it's annoying to have to do this every time, especially on Windows 10,
where the window border seems to be only one (1) pixel wide, thus making
the grabbing of the window border tricky.
Signed-off-by: James J. Raden <james.raden@gmail.com>
Since v2.9.0, Git knows about the config variable core.hookspath
that allows overriding the path to the directory containing the
Git hooks.
Since v2.10.0, the `--git-path` option respects that config
variable, too, so we may just as well use that command.
For Git versions older than v2.5.0 (which was the first version to
support the `--git-path` option for the `rev-parse` command), we
simply fall back to the previous code.
This fixes https://github.com/git-for-windows/git/issues/1755
Initial-patch-by: Philipp Gortan <philipp@gortan.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Tcl/Tk 8.6 introduced new events for the cursor left/right keys and
apparently changed the behavior of the previous event.
Let's work around that by using the new events when we are running with
Tcl/Tk 8.6 or later.
This fixes https://github.com/git-for-windows/git/issues/495
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
"Question?" is maybe not the most informative thing to ask. In the
absence of better information, it is the best we can do, of course.
However, Git for Windows' auto updater just learned the trick to use
git-gui--askyesno to ask the user whether to update now or not. And in
this scripted scenario, we can easily pass a command-line option to
change the window title.
So let's support that with the new `--title <title>` option.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make use of the new environment variable GIT_ASK_YESNO to support the
recently implemented fallback in case unlink, rename or rmdir fail for
files in use on Windows. The added dialog will present a yes/no question
to the the user which will currently be used by the windows compat layer
to let the user retry a failed file operation.
Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Git for Windows now ships with the new Git icon from git-scm.com. Use that
icon file if it exists instead of the old procedurally drawn one.
This patch was sent upstream but so far no decision on its inclusion was
made, so commit it to our fork.
Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
The text wrapping seems to be aligned to the right side of the Yes
button, leaving an awful lot of empty space.
Let's try to counter this by using pixel units.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Assumes file names in git tree objects are UTF-8 encoded.
On most unix systems, the system encoding (and thus the TCL system
encoding) will be UTF-8, so file names will be displayed correctly.
On Windows, it is impossible to set the system encoding to UTF-8.
Changing the TCL system encoding (via 'encoding system ...', e.g. in the
startup code) is explicitly discouraged by the TCL docs.
Change gitk functions dealing with file names to always convert
from and to UTF-8.
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
In MSYS2, we have two Python interpreters at our disposal, so we can
include the Python stuff in the build.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make `git config --system` work like you think it should on Windows: it
should edit the file that is located in `<Git>\etc\gitconfig`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This topic branch teaches `git clean` to respect NTFS junctions and Unix
bind mounts: it will now stop at those boundaries.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
