[PATCH 4/7] Default core.packdGitWindowSize to 1 MiB if NO_MMAP.
From: Shawn O. Pearce <hidden>
Date: 2016-06-15 22:42:46
Subsystem:
the rest · Maintainer:
Linus Torvalds
If the compiler has asked us to disable use of mmap() on their platform then we are forced to use git_mmap and its emulation via pread. In this case large (e.g. 32 MiB) windows for pack access are simply too big as a command will wind up reading a lot more data than it will ever need, significantly reducing response time. To prevent a high latency when NO_MMAP has been selected we now use a default of 1 MiB for core.packedGitWindowSize. Credit goes to Linus and Junio for recommending this more reasonable setting. Signed-off-by: Shawn O. Pearce <redacted> --- environment.c | 2 +- git-compat-util.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/environment.c b/environment.c
index 289fc84..e89aab4 100644
--- a/environment.c
+++ b/environment.c@@ -22,7 +22,7 @@ char git_commit_encoding[MAX_ENCODING_LENGTH] = "utf-8"; int shared_repository = PERM_UMASK; const char *apply_default_whitespace; int zlib_compression_level = Z_DEFAULT_COMPRESSION; -size_t packed_git_window_size = 32 * 1024 * 1024; +size_t packed_git_window_size = DEFAULT_packed_git_window_size; size_t packed_git_limit = 256 * 1024 * 1024; int pager_in_use; int pager_use_color = 1;
diff --git a/git-compat-util.h b/git-compat-util.h
index 5d9eb26..e056339 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h@@ -87,6 +87,7 @@ extern void set_warn_routine(void (*routine)(const char *warn, va_list params)); #define MAP_FAILED ((void*)-1) #endif +#define DEFAULT_packed_git_window_size (1 * 1024 * 1024) #define mmap git_mmap #define munmap git_munmap extern void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
@@ -95,6 +96,7 @@ extern int git_munmap(void *start, size_t length); #else /* NO_MMAP */ #include <sys/mman.h> +#define DEFAULT_packed_git_window_size (32 * 1024 * 1024) #endif /* NO_MMAP */
--
1.4.4.3.g2e63