Pádraig Brady wrote: > Pádraig Brady wrote: >> So in summary I would do: >> >> 1. by default always use internal PRNG seeded with getpid() >> 2. if --random-source specified read all random data from there >> >> Note 2 will allow one to specify /dev/zero if desired. >> We could seed our PRNG with /dev/urandom if available, but >> that complication is not necessary I think for this problem. > > Simple patch attached to do as above. > Note I've left `sort -R` and `shuf` reading /dev/urandom as before. > > This shows the speedup on my system with default options: > > $ shred -v -n3 t > shred: t: pass 1/3 (random)... > shred: t: pass 1/3 (random)...8.3MiB/1000MiB 0% > shred: t: pass 1/3 (random)...17MiB/1000MiB 1% > shred: t: pass 1/3 (random)...32MiB/1000MiB 3% > ... > > $ time ./shred -v t > ./shred: t: pass 1/3 (random)... > ./shred: t: pass 1/3 (random)...116MiB/1000MiB 11% > ./shred: t: pass 1/3 (random)...216MiB/1000MiB 21% > ./shred: t: pass 1/3 (random)...340MiB/1000MiB 34% > ... > > cheers, > Pádraig. >>From 005277ea7c645ae2bc1d0e88b1681b55c44348af Mon Sep 17 00:00:00 2001 > From: =?utf-8?q?P=C3=A1draig=20Brady?= <[email protected]> > Date: Mon, 6 Apr 2009 08:42:15 +0100 > Subject: [PATCH] shred: speed up random passes by not using /dev/urandom
Thanks for doing that. At first glance, you got it all. Except maybe the texinfo documentation... Yep. There's a mention of shred in the "Random sources" section. So now we'd have to say how shred's --random-source works and that its default is different from those of shuf and sort... Have you considered keeping the semantics of --random-source the same for all three programs? Things that ease the documentation burden by keeping inter-tool differences to a minimum are usually also good from usability and maintainability perspectives. _______________________________________________ Bug-coreutils mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-coreutils
