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From: mulyadi.santosa@gmail.com (Mulyadi Santosa)
To: kernelnewbies@lists.kernelnewbies.org
Subject: dd test discussion (was Re: possible regression?)
Date: Sat, 22 Jan 2011 11:49:43 +0700	[thread overview]
Message-ID: <AANLkTi=LZvUg2Auuksq1s5pw00qdgvnO3Mh1AJ8D9vRi@mail.gmail.com> (raw)

On Fri, Jan 21, 2011 at 20:25, Mag Gam <magawake@gmail.com> wrote:
> Typo, in Box 5. Wrong kernel version
>
> Box 5, RHEL 5.4, 2.6.36, dd bs=1024 count=1000000 if=/dev/zero
> bs=4096k of=/dev/null
>
> Anyone had a chance to try this? :-)

$ for a in `seq 1 3`; do \time dd bs=4K count=1M if=/dev/zero of=/dev/null; done

1048576+0 records in
1048576+0 records out
4294967296 bytes (4.3 GB) copied, 1.38893 seconds, 3.1 GB/s
0.21user 1.17system 0:01.39elapsed 99%CPU (0avgtext+0avgdata 2768maxresident)k
0inputs+0outputs (0major+209minor)pagefaults 0swaps

1048576+0 records in
1048576+0 records out
4294967296 bytes (4.3 GB) copied, 1.39358 seconds, 3.1 GB/s
0.23user 1.16system 0:01.39elapsed 99%CPU (0avgtext+0avgdata 2768maxresident)k
0inputs+0outputs (0major+209minor)pagefaults 0swaps


1048576+0 records in
1048576+0 records out
4294967296 bytes (4.3 GB) copied, 1.4527 seconds, 3.0 GB/s
0.17user 1.23system 0:01.45elapsed 96%CPU (0avgtext+0avgdata 2752maxresident)k
0inputs+0outputs (0major+208minor)pagefaults 0swaps


I slightly modified your dd test. Again, this is on 2.6.36.

IMO, you shouldn't worry much about it. Were experiencing something
that related to memory access? It's not a NUMA box, right? Or are you
using PAE? just capping into 896 MB maybe? non standart VM split other
than 3:1?

PS: I rewrite the subject to better match the discussion. With the
hope readers well get better understanding about what the discussion
is all about. Hope you don't mind....

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

             reply	other threads:[~2011-01-22  4:49 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-22  4:49 Mulyadi Santosa [this message]
2011-01-22 12:00 ` dd test discussion (was Re: possible regression?) Henry Gebhardt
2011-01-22 16:30   ` Mulyadi Santosa
2011-01-22 20:09     ` Henry Gebhardt
2011-01-23  3:25       ` Mulyadi Santosa
2011-01-22 17:41   ` Mulyadi Santosa

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