From: "Brian J. Murrell" <brian@interlinx.bc.ca>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] multiple crypt devices not using multiple CPUs
Date: Sun, 16 Dec 2012 17:02:18 -0500 [thread overview]
Message-ID: <50CE44EA.5080009@interlinx.bc.ca> (raw)
In-Reply-To: <50CE3C33.2040900@gmail.com>
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On 12-12-16 04:25 PM, Milan Broz wrote:
>
> In current kernels, work keeps on cpu which submitted it.
So a single process doing parallel reads from multiple devices (I'm sure
you could guess where I'm going with this) will never see more
throughput than it would from a single device? If so, all the more
reason to get multi-core support (for a single process of course)
involved. :-/
> Please read
> http://www.saout.de/pipermail/dm-crypt/2012-July/002582.html
Yeah. I'm trying to see this "more processes" behavior but even the two
dds each running in different shells are still attacking the same core.
> (and try to run the second case with direct-io, iow add oflag=direct for dd)
oflag=direct?
# dd oflag=direct of=/dev/null if=/dev/mapper/t1-use bs=1M count=1000
dd: opening ‘/dev/null’: Invalid argument
I guess O_DIRECT it not valid for /dev/null.
Cheers,
b.
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prev parent reply other threads:[~2012-12-16 22:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-16 21:04 [dm-crypt] multiple crypt devices not using multiple CPUs Brian J. Murrell
2012-12-16 21:25 ` Milan Broz
2012-12-16 22:02 ` Brian J. Murrell [this message]
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