add: enable FSCache around repo_read_index_preload()#6216
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April 28, 2026 09:40
Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest `lstat()`-bound work in `git add` happens inside `repo_read_index_preload()`, which currently runs *before* `enable_fscache()` is called. Moving the enable up so the preload phase is wrapped lets the existing batched `NtQueryDirectoryFile()` cache cover the bulk of the lstat traffic. Signed-off-by: Anthony Shaw <anthonyshaw@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Fix a copy-paste bug at the end of `cmd_add()`: the cleanup site called `enable_fscache(0)` again instead of `disable_fscache()`, leaking the refcount. Harmless in a one-shot process today, but it confuses the matching enable/disable contract that callers and reviewers expect. Signed-off-by: Anthony Shaw <anthonyshaw@microsoft.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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…`vfs-2.54.0` (#902) This is a companion of #899 and git-for-windows#6216. Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest lstat-bound work in git add happens inside repo_read_index_preload(), which currently runs before enable_fscache() is called. Moving the enable up so the preload phase is wrapped lets the existing batched NtQueryDirectoryFile cache cover the bulk of the lstat traffic. This patch gave me a ~30% performance improvement on a large git repo with a batched add. Also at the end of cmd_add(): the cleanup site called enable_fscache(0) again instead of disable_fscache(), leaking the refcount.
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/add relnote feature The FSCache now accelerates more The workflow run was started |
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The FSCache now [accelerates more `git add` scenarios](git-for-windows/git#6216). Signed-off-by: gitforwindowshelper[bot] <gitforwindowshelper-bot@users.noreply.github.com>
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This is a companion of microsoft#899. Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest lstat-bound work in git add happens inside repo_read_index_preload(), which currently runs before enable_fscache() is called. Moving the enable up so the preload phase is wrapped lets the existing batched NtQueryDirectoryFile cache cover the bulk of the lstat traffic. This patch gave me a ~30% performance improvement on a large git repo with a batched add. Also at the end of cmd_add(): the cleanup site called enable_fscache(0) again instead of disable_fscache(), leaking the refcount.
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This is a companion of microsoft#899. Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest lstat-bound work in git add happens inside repo_read_index_preload(), which currently runs before enable_fscache() is called. Moving the enable up so the preload phase is wrapped lets the existing batched NtQueryDirectoryFile cache cover the bulk of the lstat traffic. This patch gave me a ~30% performance improvement on a large git repo with a batched add. Also at the end of cmd_add(): the cleanup site called enable_fscache(0) again instead of disable_fscache(), leaking the refcount.
gitforwindowshelper Bot
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This is a companion of microsoft#899. Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest lstat-bound work in git add happens inside repo_read_index_preload(), which currently runs before enable_fscache() is called. Moving the enable up so the preload phase is wrapped lets the existing batched NtQueryDirectoryFile cache cover the bulk of the lstat traffic. This patch gave me a ~30% performance improvement on a large git repo with a batched add. Also at the end of cmd_add(): the cleanup site called enable_fscache(0) again instead of disable_fscache(), leaking the refcount.
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This is a companion of microsoft#899. Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest lstat-bound work in git add happens inside repo_read_index_preload(), which currently runs before enable_fscache() is called. Moving the enable up so the preload phase is wrapped lets the existing batched NtQueryDirectoryFile cache cover the bulk of the lstat traffic. This patch gave me a ~30% performance improvement on a large git repo with a batched add. Also at the end of cmd_add(): the cleanup site called enable_fscache(0) again instead of disable_fscache(), leaking the refcount.
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This is a companion of microsoft#899.
Trace2 + GIT_TRACE_FSCACHE evidence on Windows ARM64 (Snapdragon X Elite, ReFS Dev Drive) shows that the heaviest lstat-bound work in git add happens inside repo_read_index_preload(), which currently runs before enable_fscache() is called. Moving the enable up so the preload phase is wrapped lets the existing batched NtQueryDirectoryFile cache cover the bulk of the lstat traffic. This patch gave me a ~30% performance improvement on a large git repo with a batched add.
Also at the end of cmd_add(): the cleanup site called enable_fscache(0) again instead of disable_fscache(), leaking the refcount.