-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Monday, 2013-10-21 at 00:06 -0500, Larry Finger wrote:
You need to be sure the entropy pool started with the same number of entries. If 13.1 had just been booted and 12.3 had been running for some time, that condition would not be met.
THAT could be the explanation, time since boot. I just reproduced the same short read problem in 11.4, booted right now for the purpose. cer@minas-tirith:~> time dd if=/dev/random of=sample bs=100 count=1 ; l sample ; uptime 0+1 records in 0+1 records out 17 bytes (17 B) copied, 0,0185403 s, 0,9 kB/s real 0m0.127s user 0m0.001s sys 0m0.002s - -rw-r--r-- 1 cer users 17 Oct 21 12:15 sample 12:15 up 0:05, 20 users, load average: 1,45, 1,10, 0,53 I'm continuously booting one machine or other to do tests and comparisons on 13.1, 11.4 and 12.3. So it depends on how long the particular system has been running.
Is there a difference between 12.3 and 13.1 if you feed dd from /dev/urandom?
13.1, vmplayer. cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000169929 s, 588 kB/s real 0m0.039s user 0m0.002s sys 0m0.010s cer@Eleanor4:~> cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000816311 s, 123 kB/s real 0m0.007s user 0m0.001s sys 0m0.002s cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,00132882 s, 75,3 kB/s real 0m0.005s user 0m0.000s sys 0m0.003s cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,00138129 s, 72,4 kB/s real 0m0.005s user 0m0.001s sys 0m0.002s cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,00247185 s, 40,5 kB/s real 0m0.006s user 0m0.001s sys 0m0.002s cer@Eleanor4:~> 12.3: cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 6,5235e-05 s, 1,5 MB/s real 0m0.023s user 0m0.000s sys 0m0.004s cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000396105 s, 252 kB/s real 0m0.005s user 0m0.001s sys 0m0.003s cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000155374 s, 644 kB/s real 0m0.005s user 0m0.000s sys 0m0.003s cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000235979 s, 424 kB/s real 0m0.004s user 0m0.001s sys 0m0.002s cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000197719 s, 506 kB/s real 0m0.006s user 0m0.000s sys 0m0.004s cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1 1+0 records in 1+0 records out 100 bytes (100 B) copied, 0,000226242 s, 442 kB/s real 0m0.004s user 0m0.001s sys 0m0.002s cer@eleanor3:~> Very little difference. I'll use a bigger block. 13.1: cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1000 1000+0 records in 1000+0 records out 100000 bytes (100 kB) copied, 0,0230575 s, 4,3 MB/s real 0m0.027s user 0m0.001s sys 0m0.012s cer@Eleanor4:~> time dd if=/dev/urandom of=sample bs=100 count=1000 1000+0 records in 1000+0 records out 100000 bytes (100 kB) copied, 0,0227062 s, 4,4 MB/s real 0m0.027s user 0m0.002s sys 0m0.010s cer@Eleanor4:~> 12.3 cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1000 1000+0 records in 1000+0 records out 100000 bytes (100 kB) copied, 0,0380396 s, 2,6 MB/s real 0m0.044s user 0m0.001s sys 0m0.036s cer@eleanor3:~> time dd if=/dev/urandom of=sample bs=100 count=1000 1000+0 records in 1000+0 records out 100000 bytes (100 kB) copied, 0,0381175 s, 2,6 MB/s real 0m0.044s user 0m0.000s sys 0m0.036s cer@eleanor3:~> 13.1 is actually faster. - -- Cheers, Carlos E. R. (from 12.3 x86_64 "Dartmouth" at Telcontar) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iEYEARECAAYFAlJlAvMACgkQtTMYHG2NR9U7kQCfUIbRiSg5iTEJFbo5mR6qSt85 CPEAniom+/IeLRrBwK9v3gc9dEVcha1d =uIIW -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org