src/sbin/dump/cache.c, branch main FreeBSD source tree https://cgit-dev.freebsd.org/src/atom?h=main 2023-08-16T17:54:16Z Remove $FreeBSD$: two-line .h pattern 2023-08-16T17:54:16Z Warner Losh imp@FreeBSD.org 2023-08-16T17:54:16Z urn:sha1:b3e7694832e81d7a904a10f525f8797b753bf0d3 Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/ Readjust the cache initialization code to make it more obvious that the 2003-01-25T19:06:30Z Matthew Dillon dillon@FreeBSD.org 2003-01-25T19:06:30Z urn:sha1:049b1245befbb294115b7a41aa193b948ec69b70 cache is bypassed when disabled. Add a caching option to dump. Use -C. Note that NetBSD has a caching option 2003-01-13T19:42:41Z Matthew Dillon dillon@FreeBSD.org 2003-01-13T19:42:41Z urn:sha1:5941e412cacd0ebc654224ca69f66ae18f351b89 called -r but it takes 512 byte blocks instead of megabytes, and I felt a megabytes specification would be far more useful so I did not use the same option character. This will *greatly* improve dump performance at the cost of possibly missing filesystem changes that occur between passes, and does a fairly good job making up for the loss of buffered block devices. Caching is disabled by default to retain historical behavior. In tests, dump performance improved by about 40% when dumping / or /usr. Beware that dump forks and the cache may wind up being larger then you specify, but a more complex shared memory implementation would not produce results that are all that much better so I kept it simple for now. MFC after: 3 days