Date: Mon, 16 Oct 2006 11:54:15 -0700 From: David King <dking@ketralnis.com> To: freebsd-hardware@freebsd.org Subject: Re: Quiet computer Message-ID: <4ADE9CE4-089C-483D-B1C2-02230B045D01@ketralnis.com> In-Reply-To: <301DDDB6-A47E-448F-A145-7B2087599598@ketralnis.com> References: <78ED28FACE63744386D68D8A9D1CF5D4209C94@MAIL.corp.lumeta.com> <200610140346.22554.soralx@cydem.org> <301DDDB6-A47E-448F-A145-7B2087599598@ketralnis.com>
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Here's another run that doesn't have a constant number of bytes, so the bytes/sec might be a little more accurate ~% for BS in 1 512 $(expr 1024 \* 4) $(expr 1024 \* 16) $(expr 1024 \* 64); do dd if=/dev/random of=/dev/null bs=$BS count=1024; done 1024+0 records in 1024+0 records out 1024 bytes transferred in 0.395678 secs (2588 bytes/sec) 1024+0 records in 1024+0 records out 524288 bytes transferred in 0.791416 secs (662468 bytes/sec) 1024+0 records in 1024+0 records out 4194304 bytes transferred in 6.415680 secs (653758 bytes/sec) 1024+0 records in 1024+0 records out 16777216 bytes transferred in 25.814593 secs (649912 bytes/sec) 1024+0 records in 1024+0 records out 67108864 bytes transferred in 102.280978 secs (656123 bytes/sec) On 16 Oct 2006, at 10:14, David King wrote: >> BTW, David, test (if you have enough time for curiosity) /dev/ >> urandom (or >> wherever the generator is) with different values of 'bs', from very >> small to large (1 byte, 512, 4k, 16k, 64k) to see how much it depends >> on block size. >> >>> bash-2.05b$ time dd if=/dev/urandom bs=1024 count=10240 of=/dev/null >>> 10240+0 records in >>> 10240+0 records out >>> 10485760 bytes transferred in 0.154649 secs (67803598 bytes/sec) > > > ~% cat test_rand_block.sh > #!/usr/local/bin/bash > > for BS in 1 512 $(expr 1024 \* 4) $(expr 1024 \* 16) $(expr 1024 \* > 64); do > COUNT=$(expr $(expr 1024 \* 64) / $BS) > BYTES=$(expr $COUNT \* $BS) > > echo bs=$BS count=$COUNT bytes=$BYTES > > dd if=/dev/random of=/dev/null bs=$BS count=$COUNT > > echo ------; > done > ~% sh test_rand_block.sh > bs=1 count=65536 bytes=65536 > 65536+0 records in > 65536+0 records out > 65536 bytes transferred in 25.599306 secs (2560 bytes/sec) > ------ > bs=512 count=128 bytes=65536 > 128+0 records in > 128+0 records out > 65536 bytes transferred in 0.099902 secs (656003 bytes/sec) > ------ > bs=4096 count=16 bytes=65536 > 16+0 records in > 16+0 records out > 65536 bytes transferred in 0.100660 secs (651062 bytes/sec) > ------ > bs=16384 count=4 bytes=65536 > 4+0 records in > 4+0 records out > 65536 bytes transferred in 0.099324 secs (659820 bytes/sec) > ------ > bs=65536 count=1 bytes=65536 > 1+0 records in > 1+0 records out > 65536 bytes transferred in 0.099681 secs (657458 bytes/sec) > ------ > > _______________________________________________ > freebsd-hardware@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hardware > To unsubscribe, send any mail to "freebsd-hardware- > unsubscribe@freebsd.org" -- David King Computer Programmer Ketralnis Systems
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