path: root/t/helper/test-path-utils.c
diff options
authorJohannes Schindelin <>2019-01-29 14:19:38 (GMT)
committerJunio C Hamano <>2019-01-29 17:26:47 (GMT)
commitb819f1d2cec91e8c81b4d92ec787979ab2721aa6 (patch)
treeaef39b932e1dcf935abb6e38a87ceafe22ea075e /t/helper/test-path-utils.c
parenta87e427e35fc79677dd85d591a7b37fb2539189a (diff)
ci: parallelize testing on Windows
The fact that Git's test suite is implemented in Unix shell script that is as portable as we can muster, combined with the fact that Unix shell scripting is foreign to Windows (and therefore has to be emulated), results in pretty abysmal speed of the test suite on that platform, for pretty much no other reason than that language choice. For comparison: while the Linux build & test is typically done within about 8 minutes, the Windows build & test typically lasts about 80 minutes in Azure Pipelines. To help with that, let's use the Azure Pipeline feature where you can parallelize jobs, make jobs depend on each other, and pass artifacts between them. The tests are distributed using the following heuristic: listing all test scripts ordered by size in descending order (as a cheap way to estimate the overall run time), every Nth script is run (where N is the total number of parallel jobs), starting at the index corresponding to the parallel job. This slicing is performed by a new function that is added to the `test-tool`. To optimize the overall runtime of the entire Pipeline, we need to move the Windows jobs to the beginning (otherwise there would be a very decent chance for the Pipeline to be run only the Windows build, while all the parallel Windows test jobs wait for this single one). We use Azure Pipelines Artifacts for both the minimal Git for Windows SDK as well as the built executables, as deduplication and caching close to the agents makes that really fast. For comparison: while downloading and unpacking the minimal Git for Windows SDK via PowerShell takes only one minute (down from anywhere between 2.5 to 7 when using a shallow clone), uploading it as Pipeline Artifact takes less than 30s and downloading and unpacking less than 20s (sometimes even as little as only twelve seconds). Signed-off-by: Johannes Schindelin <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 't/helper/test-path-utils.c')
1 files changed, 31 insertions, 0 deletions
diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
index 6efde6f..5d543ad 100644
--- a/t/helper/test-path-utils.c
+++ b/t/helper/test-path-utils.c
@@ -177,6 +177,14 @@ static int is_dotgitmodules(const char *path)
return is_hfs_dotgitmodules(path) || is_ntfs_dotgitmodules(path);
+static int cmp_by_st_size(const void *a, const void *b)
+ intptr_t x = (intptr_t)((struct string_list_item *)a)->util;
+ intptr_t y = (intptr_t)((struct string_list_item *)b)->util;
+ return x > y ? -1 : (x < y ? +1 : 0);
int cmd__path_utils(int argc, const char **argv)
if (argc == 3 && !strcmp(argv[1], "normalize_path_copy")) {
@@ -324,6 +332,29 @@ int cmd__path_utils(int argc, const char **argv)
return 0;
+ if (argc > 5 && !strcmp(argv[1], "slice-tests")) {
+ int res = 0;
+ long offset, stride, i;
+ struct string_list list = STRING_LIST_INIT_NODUP;
+ struct stat st;
+ offset = strtol(argv[2], NULL, 10);
+ stride = strtol(argv[3], NULL, 10);
+ if (stride < 1)
+ stride = 1;
+ for (i = 4; i < argc; i++)
+ if (stat(argv[i], &st))
+ res = error_errno("Cannot stat '%s'", argv[i]);
+ else
+ string_list_append(&list, argv[i])->util =
+ (void *)(intptr_t)st.st_size;
+ QSORT(list.items,, cmp_by_st_size);
+ for (i = offset; i <; i+= stride)
+ printf("%s\n", list.items[i].string);
+ return !!res;
+ }
fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
argv[1] ? argv[1] : "(there was none)");
return 1;