4 Commits

Author	SHA1	Message	Date
Rusty Russell	11ab43084b	tdb: workaround starvation problem in locking entire database. ... We saw tdb_lockall() take 71 seconds under heavy load; this is because Linux (at least) doesn't prevent new small locks being obtained while we're waiting for a big log. The workaround is to do divide and conquer using non-blocking chainlocks: if we get down to a single chain we block. Using a simple test program where children did "hold lock for 100ms, sleep for 1 second" the time to do tdb_lockall() dropped signifiantly. There are ln(hashsize) locks taken in the contended case, but that's slow anyway. More analysis is given in my blog at http://rusty.ozlabs.org/?p=120 This may also help transactions, though in that case it's the initial read lock which uses this gradual locking routine; the update-to-write-lock code is separate and still tries to update in one go. Even though ABI doesn't change, minor version bumped so behavior change can be easily detected. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>	2010-08-14 02:31:22 +09:30
Stefan Metzmacher	b81887f2d9	tdb: commit ABI/tdb-1.2.2.sigs ... metze	2010-05-11 18:11:05 +02:00
Andrew Tridgell	f96353adcf	s4-waf: rebuild signature files with the api type maps ... This is not strictly necessary, as the old types would compare equal, but it is neater to use the generic type names	2010-04-18 15:39:59 +10:00
Andrew Tridgell	805f651dbf	tdb-waf: added ABI checking for tdb	2010-04-18 15:00:38 +10:00