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>
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>
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>
This is the branch thicket of patches in Git for Windows that are
considered ready for upstream. To keep them in a ready-to-submit shape,
they are kept as close to the beginning of the branch thicket as
possible.
This merges the current version of the patch that tries to address Git
GUI's problems with intent-to-add files.
This patch will likely be improved substantially before it is merged
into Git GUI's main branch, but we want to have _something_ resembling a
fix already in Git for Windows v2.29.0.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This topic branch allows `add -p` and `add -i` with a large number of
files. It is kind of a hack that was never really meant to be
upstreamed. Let's see if we can do better in the built-in `add -p`.
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>
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>
Add basic performance tests for git commands that can add data to the
object database. We cover:
* git add
* git stash
* git update-index (via git stash)
* git unpack-objects
* git commit --all
We cover all currently available fsync methods as well.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To verify that the `clean` side of the `clean`/`smudge` filter code is
correct with regards to LLP64 (read: to ensure that `size_t` is used
instead of `unsigned long`), here is a test case using a trivial filter,
specifically _not_ writing anything to the object store to limit the
scope of the test case.
As in previous commits, the `big` file from previous test cases is
reused if available, to save setup time, otherwise re-generated.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
If `feature.experimental` and `feature.manyFiles` are set and the user
has not explicitly turned off the builtin FSMonitor, we now start
the built-in FSMonitor by default.
Only forcing it when UNSET matches the behavior of UPDATE_DEFAULT_BOOL()
used for other repo settings.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Confirm that the daemon reports events using the on-disk
spelling for Unicode NFC/NFD characters. On APFS we still
have Unicode aliasing, so we cannot create two files that
only differ by NFC/NFD, but the on-disk format preserves
the spelling used to create the file. On HFS+ we also
have aliasing, but the path is always stored on disk in
NFD.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
This topic branch avoids spawning `gzip` when asking `git archive` to
create `.tar.gz` files.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Tests that affect the repo in stateful ways are easier to write if we
can run setup steps outside of the measured portion of perf iteration.
This change adds a "--setup 'setup-script'" parameter to test_perf. To
make invocations easier to understand, I also moved the prerequisites to
a new --prereq parameter.
The setup facility will be used in the upcoming perf tests for batch
mode, but it already helps in some existing tests, like t5302 and t7820.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To complement the `--stdin` and `--literally` test cases that verify
that we can hash files larger than 4GB on 64-bit platforms using the
LLP64 data model, here is a test case that exercises `hash-object`
_without_ any options.
Just as before, we use the `big` file from the previous test case if it
exists to save on setup time, otherwise generate it.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
