Thank you Jorrit for your detailed answer. > On 18 May 2020, at 17:58, Jorrit Jongma via rsync <rsync@lists.samba.org> > wrote: > > Well, don't get too excited, get_checksum1() (the function optimized > here) is not the great performance limiter in this case, it's > get_checksum2() and sum_update(), which will be using MD5.
Certainly that all other functions using MD5 could be updated to use your SSE-optimized function. So that we have a full SSE MD5 support, wherever rsync is using it (basis file checksum, rolling checksum etc...). I think one nice performance improvement could be when the receiver checksums the (big/huge) basis file, because here the sender is then simply waiting... > Unfortunately, single stream MD5 cannot be effectively optimized with > SSE, at least I've not seen an SSE version faster than pure C I was about to tell you that we successfully implemented it into FreeBSD a few years ago, but it's CRC32, not MD5... https://github.com/freebsd/freebsd/commit/c4b27423f57c30068aff3f234c912ae8d9ff1b6a https://github.com/freebsd/freebsd/commit/5a798b035b4858923878c014a5faa48b2f9aa6e7 At least sounds like the algorithm author / inspiration, Mark Adler, is the same :) Anyway, this is a first interesting SSE MD5 support. -- Please use reply-all for most replies to avoid omitting the mailing list. To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
