{"thread":{"id":"36219","subject":"[PATCH] Bump core.deltaBaseCacheLimit to 128MiB","startedAt":"2014-03-19T09:13:39Z","lastAt":"2014-03-19T09:13:39Z","messageCount":1,"participants":["David Kastrup"],"isPatch":true,"patchVersion":1,"patchTotal":null},"messages":[{"id":"237050","messageId":"1395220419-4541-1-git-send-email-dak@gnu.org","threadId":"36219","inReplyTo":null,"subject":"[PATCH] Bump core.deltaBaseCacheLimit to 128MiB","fromName":"David Kastrup","fromEmail":"dak@gnu.org","sentAt":"2014-03-19T09:13:39Z","receivedAt":"2014-03-19T09:13:39Z","isPatch":true,"sender":{"key":"dak@gnu.org","avatar":"https://avatars.githubusercontent.com/u/52141349?v=4"},"body":"The default of 16MiB causes serious thrashing for large delta chains\ncombined with large files.\n---\n128MiB seems like a big bump, but the limit for files not getting\ndelta compressed at all is 512MiB and it would appear that they should\nbe a bit comparable.  It is hard to find good benchmarks here:\nbasically the best benchmark I found was git blame with\nproblematically large repositories compressed with the (old)\ngit-gc --aggressive settings, using not-yet-committed but presented\ncode (the current blame code spends so much time thrashing in other\nplaces that the benchmark differences are less obvious).\n\nDocumentation/config.txt | 2 +-\n environment.c            | 2 +-\n 2 files changed, 2 insertions(+), 2 deletions(-)\n\ndiff --git a/Documentation/config.txt b/Documentation/config.txt\nindex 73c8973..1b6950a 100644\n--- a/Documentation/config.txt\n+++ b/Documentation/config.txt\n@@ -484,7 +484,7 @@ core.deltaBaseCacheLimit::\n \tto avoid unpacking and decompressing frequently used base\n \tobjects multiple times.\n +\n-Default is 16 MiB on all platforms.  This should be reasonable\n+Default is 128 MiB on all platforms.  This should be reasonable\n for all users/operating systems, except on the largest projects.\n You probably do not need to adjust this value.\n +\ndiff --git a/environment.c b/environment.c\nindex c3c8606..73ed670 100644\n--- a/environment.c\n+++ b/environment.c\n@@ -37,7 +37,7 @@ int core_compression_seen;\n int fsync_object_files;\n size_t packed_git_window_size = DEFAULT_PACKED_GIT_WINDOW_SIZE;\n size_t packed_git_limit = DEFAULT_PACKED_GIT_LIMIT;\n-size_t delta_base_cache_limit = 16 * 1024 * 1024;\n+size_t delta_base_cache_limit = 128 * 1024 * 1024;\n unsigned long big_file_threshold = 512 * 1024 * 1024;\n const char *pager_program;\n int pager_use_color = 1;\n-- \n1.8.3.2\n"}]}