On 9/27/2018 11:21 AM, Ben Peart wrote:
On 9/26/2018 2:54 PM, Derrick Stolee wrote:
GIT_TEST_INDEX_THREADS=1
Because the test repos are so small (ie smaller than 10K files), the
test suite already executes as if GIT_TEST_INDEX_THREADS=1 is set (ie
single threaded). I added the test variable so that the
multi-threading code could be forced to execute in spite of the
default minimum number of files logic.
I'd recommend you set GIT_TEST_INDEX_THREADS=3 instead. (3 because 1
thread is used for loading the index extensions and we need 2 or more
threads available to exercise multi-threaded loading of the index
entries).
According to t/README, GIT_TEST_INDEX_THREADS is a boolean and setting
it to 1 causes us to use 3 threads:
GIT_TEST_INDEX_THREADS=<boolean> forces multi-threaded loading of
the index cache entries and extensions for the whole test suite.
Here is the only consumption of the variable in the product code (in
read-cache.c):
/* enable testing with fewer than default minimum of entries */
if (istate->cache_nr > 1 && nr_threads < 3 &&
git_env_bool("GIT_TEST_INDEX_THREADS", 0))
nr_threads = 3;
This was non-obvious to me, and I had originally set it to a larger
number. I happened to notice the boolean nature while I was looking up
the rest of the GIT_TEST_* variables.
Thanks,
-Stolee
