git/contrib/buildsystems
Neeraj Singh abf38abec2 core.fsyncmethod: add writeout-only mode
This commit introduces the `core.fsyncMethod` configuration
knob, which can currently be set to `fsync` or `writeout-only`.

The new writeout-only mode attempts to tell the operating system to
flush its in-memory page cache to the storage hardware without issuing a
CACHE_FLUSH command to the storage controller.

Writeout-only fsync is significantly faster than a vanilla fsync on
common hardware, since data is written to a disk-side cache rather than
all the way to a durable medium. Later changes in this patch series will
take advantage of this primitive to implement batching of hardware
flushes.

When git_fsync is called with FSYNC_WRITEOUT_ONLY, it may fail and the
caller is expected to do an ordinary fsync as needed.

On Apple platforms, the fsync system call does not issue a CACHE_FLUSH
directive to the storage controller. This change updates fsync to do
fcntl(F_FULLFSYNC) to make fsync actually durable. We maintain parity
with existing behavior on Apple platforms by setting the default value
of the new core.fsyncMethod option.

Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-10 15:10:22 -08:00
..
Generators reftable: utility functions 2021-10-08 10:45:48 -07:00
CMakeLists.txt core.fsyncmethod: add writeout-only mode 2022-03-10 15:10:22 -08:00
engine.pl ci(vs-build): stop passing the iconv library location explicitly 2020-12-04 12:03:15 -08:00
generate mark Windows build scripts executable 2013-11-25 15:01:22 -08:00
Generators.pm contrib/buildsystems: ignore irrelevant files in Generators/ 2019-07-29 14:51:42 -07:00
parse.pl mark Windows build scripts executable 2013-11-25 15:01:22 -08:00