From: "George Spelvin" <linux@horizon.com>
To: linux@horizon.com, tytso@mit.edu
Cc: hpa@linux.intel.com, linux-kernel@vger.kernel.org,
mingo@kernel.org, price@mit.edu
Subject: Re: [RFC PATCH] drivers/char/random.c: Is reducing locking range like this safe?
Date: 9 Jun 2014 05:23:17 -0400 [thread overview]
Message-ID: <20140609092317.17828.qmail@ns.horizon.com> (raw)
In-Reply-To: <20140609040355.8126.qmail@ns.horizon.com>
> Sigh, adventures in "unable to mount root filesystem" currently underway.
PEBKAC resolved. (I had CONFIG_ATA=m for some testing, but forgot
to change it back to y when compiling a kernel I expected to boot.)
32 MiB write:
Without patch With patch
0 readers: 0.495523 0.494998 0.515995 0.516026
1 reader: 0.842245 0.845308 0.704283 0.704318
2 readers: 1.18658 1.18762 0.904635 0.904844
3 readers: 1.49615 1.49616 1.14311 1.16836
I haven't rebooted back to the without-patch kernel to see if the 20 ms
loss is consistent, but obviously that needs fixing. (There's more than
just that patch I posted in there.)
Anyway, it's noticeable, but maybe not worth fixing.
The interesting question is whether we should get rid of out[].
That's obscurity that contributes no security, and thus a Bad
Thing by definition.
next prev parent reply other threads:[~2014-06-09 9:23 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-09 0:05 George Spelvin
2014-06-09 1:35 ` Theodore Ts'o
2014-06-09 2:10 ` George Spelvin
2014-06-09 2:18 ` George Spelvin
2014-06-09 4:03 ` George Spelvin
2014-06-09 9:23 ` George Spelvin [this message]
2014-06-09 13:34 ` Theodore Ts'o
2014-06-09 15:04 ` George Spelvin
2014-06-09 15:50 ` Theodore Ts'o
2014-06-09 16:11 ` George Spelvin
2014-06-10 0:20 ` drivers/char/random.c: more ruminations George Spelvin
2014-06-10 1:20 ` Theodore Ts'o
2014-06-10 3:10 ` George Spelvin
2014-06-10 15:25 ` Theodore Ts'o
2014-06-10 20:40 ` George Spelvin
2014-06-10 21:20 ` Theodore Ts'o
2014-06-11 0:10 ` George Spelvin
2014-06-11 2:08 ` Theodore Ts'o
2014-06-11 3:58 ` George Spelvin
2014-06-11 13:11 ` Theodore Ts'o
2014-06-12 0:42 ` George Spelvin
2014-06-12 1:03 ` H. Peter Anvin
2014-06-11 4:34 ` George Spelvin
2014-06-11 13:09 ` Theodore Ts'o
2014-06-11 2:21 ` Theodore Ts'o
2014-06-09 13:17 ` drivers/char/random.c: More futzing about George Spelvin
2014-06-11 16:38 ` Theodore Ts'o
2014-06-11 16:48 ` H. Peter Anvin
2014-06-11 19:25 ` Theodore Ts'o
2014-06-11 20:41 ` H. Peter Anvin
2014-06-12 0:44 ` H. Peter Anvin
2014-06-12 1:51 ` George Spelvin
2014-06-12 0:32 ` George Spelvin
2014-06-12 3:22 ` Theodore Ts'o
2014-06-12 4:13 ` random: Benchamrking fast_mix2 George Spelvin
2014-06-12 11:18 ` George Spelvin
2014-06-12 20:17 ` Theodore Ts'o
2014-06-12 20:46 ` Theodore Ts'o
2014-06-13 0:23 ` George Spelvin
2014-06-13 15:52 ` Theodore Ts'o
2014-06-14 2:10 ` George Spelvin
2014-06-14 3:06 ` Theodore Ts'o
2014-06-14 5:25 ` George Spelvin
2014-06-14 6:24 ` Theodore Ts'o
2014-06-14 8:03 ` George Spelvin
2014-06-14 11:14 ` George Spelvin
2014-06-14 15:13 ` George Spelvin
2014-06-14 16:33 ` Theodore Ts'o
2014-06-15 0:23 ` George Spelvin
2014-06-15 1:17 ` Theodore Ts'o
2014-06-15 6:58 ` George Spelvin
2014-06-15 13:01 ` Theodore Ts'o
2014-06-14 6:27 ` Theodore Ts'o
2014-06-14 4:55 ` [RFC] random: is the IRQF_TIMER test working as intended? George Spelvin
2014-06-14 6:43 ` Theodore Ts'o
2014-06-14 7:23 ` George Spelvin
2014-06-12 3:43 ` drivers/char/random.c: More futzing about George Spelvin
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