path: root/builtin/cat-file.c
diff options
authorJeff King <>2016-05-18 16:56:14 (GMT)
committerJunio C Hamano <>2016-05-18 21:17:39 (GMT)
commit6a36e1e7bb64726cc712259aff57179d81361b5d (patch)
treedde1800135b1482f081ad144471d80e6a67cd654 /builtin/cat-file.c
parent845de33a5b2c9efb7761d091f1475ec89c25798a (diff)
cat-file: default to --buffer when --batch-all-objects is used
Traditionally cat-file's batch-mode does not do any output buffering. The reason is that a caller may have pipes connected to its input and output, and would want to use cat-file interactively, getting output immediately for each input it sends. This may involve a lot of small write() calls, which can be slow. So we introduced --buffer to improve this, but we can't turn it on by default, as it would break the interactive case above. However, when --batch-all-objects is used, we do not read stdin at all. We generate the output ourselves as quickly as possible, and then exit. In this case buffering is a strict win, and it is simply a hassle for the user to have to remember to specify --buffer. This patch makes --buffer the default when --batch-all-objects is used. Specifying "--buffer" manually is still OK, and you can even override it with "--no-buffer" if you're a masochist (or debugging). For some real numbers, running: git cat-file --batch-all-objects --batch-check='%(objectname)' on torvalds/linux goes from: real 0m1.464s user 0m1.208s sys 0m0.252s to: real 0m1.230s user 0m1.172s sys 0m0.056s for a 16% speedup. Suggested-by: Charles Bailey <> Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'builtin/cat-file.c')
1 files changed, 4 insertions, 0 deletions
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 144ae18..8f114ad 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -504,6 +504,7 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
git_config(git_cat_file_config, NULL);
+ batch.buffer_output = -1;
argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
if (opt) {
@@ -527,6 +528,9 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
usage_with_options(cat_file_usage, options);
+ if (batch.buffer_output < 0)
+ batch.buffer_output = batch.all_objects;
if (batch.enabled)
return batch_objects(&batch);