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From: Willy Tarreau <w@1wt.eu>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: George Spelvin <lkml@sdf.org>, Amit Klein <aksecurity@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	"Jason A. Donenfeld" <Jason@zx2c4.com>,
	Andy Lutomirski <luto@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	netdev@vger.kernel.org
Subject: Re: [DRAFT PATCH] random32: make prandom_u32() output unpredictable
Date: Fri, 14 Aug 2020 18:05:51 +0200	[thread overview]
Message-ID: <20200814160551.GA11657@1wt.eu> (raw)
In-Reply-To: <CA+icZUW8oD6BLnyFUzXHS8fFciLaLQAZnus7GgUdCuSZcMg+MQ@mail.gmail.com>

On Fri, Aug 14, 2020 at 05:32:32PM +0200, Sedat Dilek wrote:
> commit 94c7eb54c4b8e81618ec79f414fe1ca5767f9720
> "random32: add a tracepoint for prandom_u32()"
> 
> ...I gave Willy's patches a try and used the Linux Test Project (LTP)
> for testing.

Just FWIW today I could run several relevant tests with a 40 Gbps NIC
at high connection rates and under SYN flood to stress SYN cookies.
I couldn't post earlier due to a net outage but will post the results
here. In short, what I'm seeing is very good. The only thing is that
the noise collection as-is with the 4 longs takes a bit too much CPU
(0.2% measured) but if keeping only one word we're back to tausworthe
performance, while using siphash all along.

The noise generation function is so small that we're wasting cycles
calling it and renaming registers. I'll run one more test by inlining
it and exporting the noise.

So provided quite some cleanup now, I really think we're about to
reach a solution which will satisfy everyone. More on this after I
extract the results.

Willy

  reply	other threads:[~2020-08-14 16:06 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CA+icZUVnsmf1kXPYFYufStQ_MxnLuxL+EWfDS2wQy1VbAEMwkA@mail.gmail.com>
2020-08-09 21:10 ` [DRAFT PATCH] random32: make prandom_u32() output unpredictable Sedat Dilek
     [not found] ` <20200809235412.GD25124@SDF.ORG>
     [not found]   ` <20200810034948.GB8262@1wt.eu>
     [not found]     ` <20200811053455.GH25124@SDF.ORG>
     [not found]       ` <20200811054328.GD9456@1wt.eu>
     [not found]         ` <20200811062814.GI25124@SDF.ORG>
     [not found]           ` <20200811074538.GA9523@1wt.eu>
2020-08-11 10:51             ` Sedat Dilek
2020-08-11 11:01               ` Sedat Dilek
2020-08-12  3:21               ` Willy Tarreau
2020-08-13  7:53                 ` Sedat Dilek
2020-08-13  8:06                   ` Willy Tarreau
2020-08-13  8:13                     ` Sedat Dilek
2020-08-13  8:27                       ` Sedat Dilek
2020-08-13 14:00                         ` Eric Dumazet
2020-08-13 16:02                           ` Sedat Dilek
2020-08-14 15:32                     ` Sedat Dilek
2020-08-14 16:05                       ` Willy Tarreau [this message]
2020-08-14 16:17                         ` Sedat Dilek
2020-08-16 15:01                           ` Willy Tarreau
2020-08-16 16:48                             ` Sedat Dilek
2020-08-20  3:05                               ` Sedat Dilek
2020-08-20  4:33                                 ` Willy Tarreau
2020-08-20  4:42                                   ` Sedat Dilek
2020-08-20  6:08                                     ` Willy Tarreau
2020-08-20  6:58                                       ` Willy Tarreau
2020-08-20  8:05                                         ` Willy Tarreau
2020-08-20 12:08                                           ` Sedat Dilek
     [not found]                                           ` <CANEQ_+L+22Hkdqf38Zr0bfq16fcL1Ax2X9fToXV_niHKXCB8aA@mail.gmail.com>
2020-08-27  1:09                                             ` Willy Tarreau
2020-08-27  7:08                                               ` Sedat Dilek
2020-08-08 15:26 Flaw in "random32: update the net random state on interrupt and activity" George Spelvin
2020-08-09  6:57 ` [DRAFT PATCH] random32: make prandom_u32() output unpredictable George Spelvin
2020-08-09  9:38   ` Willy Tarreau
2020-08-09 17:06     ` George Spelvin
2020-08-09 17:33       ` Willy Tarreau
2020-08-09 18:30         ` George Spelvin
2020-08-09 19:16           ` Willy Tarreau
2020-08-10 11:47           ` Willy Tarreau
2020-08-10 12:01             ` David Laight
2020-08-10 14:48               ` Willy Tarreau
2020-08-10 12:03             ` Florian Westphal
2020-08-10 14:53               ` Willy Tarreau
2020-08-10 16:31             ` Linus Torvalds
2020-08-10 16:58               ` Willy Tarreau
2020-08-10 17:45                 ` Linus Torvalds
2020-08-10 18:01                   ` Willy Tarreau
2020-08-10 21:04                   ` Willy Tarreau
2020-08-11  5:26                     ` George Spelvin
2020-08-11  5:37                       ` Willy Tarreau
2020-08-11  3:47             ` George Spelvin
2020-08-11  3:58               ` Willy Tarreau
     [not found]     ` <fdbc7d7d-cba2-ef94-9bde-b3ccae0cfaac@gmail.com>
2020-08-09 21:10       ` Marc Plumb
2020-08-09 21:48         ` Linus Torvalds
2020-08-09 13:50   ` Randy Dunlap
     [not found]   ` <CANEQ_++a4YcwQQ2XhuguTono9=RxbSRVsMw08zLWBWJ_wxG2AQ@mail.gmail.com>
2020-08-09 16:08     ` George Spelvin

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