From: Joey Hess <joeyh@joeyh.name>
Date: Thu, 9 Apr 2020 18:09:41 +0000 (-0400)
Subject: new optimisation target
X-Git-Tag: archive/raspbian/10.20250416-2+rpi1~2^2^2~96^2~790
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=5e4423c0588a2669c90d0f0962f311556a5e3913;p=git-annex.git

new optimisation target
---

diff --git a/doc/todo/optimise_by_using_RawFilePath_for_gitAnnexIndex.mdwn b/doc/todo/optimise_by_using_RawFilePath_for_gitAnnexIndex.mdwn
new file mode 100644
index 0000000000..11d9f0cb8c
--- /dev/null
+++ b/doc/todo/optimise_by_using_RawFilePath_for_gitAnnexIndex.mdwn
@@ -0,0 +1,26 @@
+Profiling `git annex find --in web` found that a single decodeFilePath in
+gitAnnexIndex uses 1.4% of time.
+
+The call path is getRef to withIndex to gitAnnexIndex.
+
+The FilePath is put into the environment. Switching to use RawFilePath
+environment when running processes would be a bit involved, because
+System.Process does not support it and would need to be modified/forked.
+(The rawfilepath package did it, but unfortunately also changed its API in
+other ways.)
+
+However... git-annex starts up a single, long-running git cat-file
+process. The only reason it needs to get gitAnnexIndex after that is
+running is to select the git process that is using the right index file.
+
+So, one way would be to make withIndexFile less generic,
+eg a withAnnexIndexFile that does not need the filename to be calculated
+each time.
+
+Or, keep withIndexFile generic but change Annex.cachedgitenv to contain
+ByteStrings, and convert to FilePath only when that environment is used to
+start a new process. (This seems like it would be a little slower than
+the other alternative, since constructing a RawFilePath is also not
+entirely without cost, although significantly faster.)
+
+--[[Joey]]