From 7af607c58d7985a0eb70fc3bca6eef8eb2381f14 Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Wed, 3 Jan 2024 07:22:30 +0100 Subject: reftable/record: store "val1" hashes as static arrays When reading ref records of type "val1", we store its object ID in an allocated array. This results in an additional allocation for every single ref record we read, which is rather inefficient especially when iterating over refs. Refactor the code to instead use an embedded array of `GIT_MAX_RAWSZ` bytes. While this means that `struct ref_record` is bigger now, we typically do not store all refs in an array anyway and instead only handle a limited number of records at the same point in time. Using `git show-ref --quiet` in a repository with ~350k refs this leads to a significant drop in allocations. Before: HEAP SUMMARY: in use at exit: 21,098 bytes in 192 blocks total heap usage: 2,116,683 allocs, 2,116,491 frees, 76,098,060 bytes allocated After: HEAP SUMMARY: in use at exit: 21,098 bytes in 192 blocks total heap usage: 1,419,031 allocs, 1,418,839 frees, 62,145,036 bytes allocated Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- reftable/readwrite_test.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'reftable/readwrite_test.c') diff --git a/reftable/readwrite_test.c b/reftable/readwrite_test.c index 9c16e0504e..87b238105c 100644 --- a/reftable/readwrite_test.c +++ b/reftable/readwrite_test.c @@ -60,18 +60,15 @@ static void write_table(char ***names, struct strbuf *buf, int N, *names = reftable_calloc(sizeof(char *) * (N + 1)); reftable_writer_set_limits(w, update_index, update_index); for (i = 0; i < N; i++) { - uint8_t hash[GIT_SHA256_RAWSZ] = { 0 }; char name[100]; int n; - set_test_hash(hash, i); - snprintf(name, sizeof(name), "refs/heads/branch%02d", i); ref.refname = name; ref.update_index = update_index; ref.value_type = REFTABLE_REF_VAL1; - ref.value.val1 = hash; + set_test_hash(ref.value.val1, i); (*names)[i] = xstrdup(name); n = reftable_writer_add_ref(w, &ref); @@ -675,11 +672,10 @@ static void test_write_object_id_min_length(void) struct strbuf buf = STRBUF_INIT; struct reftable_writer *w = reftable_new_writer(&strbuf_add_void, &buf, &opts); - uint8_t hash[GIT_SHA1_RAWSZ] = {42}; struct reftable_ref_record ref = { .update_index = 1, .value_type = REFTABLE_REF_VAL1, - .value.val1 = hash, + .value.val1 = {42}, }; int err; int i; @@ -711,11 +707,10 @@ static void test_write_object_id_length(void) struct strbuf buf = STRBUF_INIT; struct reftable_writer *w = reftable_new_writer(&strbuf_add_void, &buf, &opts); - uint8_t hash[GIT_SHA1_RAWSZ] = {42}; struct reftable_ref_record ref = { .update_index = 1, .value_type = REFTABLE_REF_VAL1, - .value.val1 = hash, + .value.val1 = {42}, }; int err; int i; @@ -814,11 +809,10 @@ static void test_write_multiple_indices(void) writer = reftable_new_writer(&strbuf_add_void, &writer_buf, &opts); reftable_writer_set_limits(writer, 1, 1); for (i = 0; i < 100; i++) { - unsigned char hash[GIT_SHA1_RAWSZ] = {i}; struct reftable_ref_record ref = { .update_index = 1, .value_type = REFTABLE_REF_VAL1, - .value.val1 = hash, + .value.val1 = {i}, }; strbuf_reset(&buf); -- cgit v1.3