On 2013-04-18 00:44:02 +0300, Ants Aasma wrote: > I went ahead and coded up both the parallel FNV-1a and parallel FNV-1a > + srl1-xor variants and ran performance tests and detection rate tests > on both. > > Performance results: > Mul-add checksums: 12.9 bytes/s > FNV-1a checksums: 13.5 bytes/s > FNV-1a + srl-1: 7.4 bytes/s > > Detection rates: > False positive rates: > Add-mul FNV-1a FNV-1a + srl-1 > Single bit flip: 1:inf 1:129590 1:64795 > Double bit flip: 1:148 1:511 1:53083 > Triple bit flip: 1:673 1:5060 1:61511 > Quad bit flip: 1:1872 1:19349 1:68320 > Write 0x00 byte: 1:774538137 1:118776 1:68952 > Write 0xFF byte: 1:165399500 1:137489 1:68958 > Partial write: 1:59949 1:71939 1:89923 > Write garbage: 1:64866 1:64980 1:67732 > Write run of 00: 1:57077 1:61140 1:59723 > Write run of FF: 1:63085 1:59609 1:62977 > > Test descriptions: > N bit flip: picks N random non-overlapping bits and flips their value. > Write X byte: overwrites a single byte with X. > Partial write: picks a random cut point, overwrites everything from > there to end with 0x00. > Write garbage/run of X: picks two random cut points and fills > everything in between with random values/X bytes.
I don't think this table is complete without competing numbers for truncated crc-32. Any chance to get that? Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
