Date: Wed, 25 Jul 2012 06:24:05 -0400 From: Richard Yao <ryao@gentoo.org> To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> Cc: Richard Yao <ryao@gentoo.org>, "hackers@FreeBSD.org" <hackers@freebsd.org>, "ivoras@freebsd.org" <ivoras@freebsd.org>, Adrian Chadd <adrian@freebsd.org>, "current@freebsd.org" <current@freebsd.org> Subject: Re: Awful FreeBSD 9 block IO performance in KVM Message-ID: <500FC945.8010602@gentoo.org> In-Reply-To: <63653b2570964cb995f7191fabdb52c8@HUBCAS2.cs.stonybrook.edu> References: <50085193.6030203@gentoo.org> <CAJ-VmonynbAq8XaV_-dM7aEpQ1p33P3vHA1TMjsDs=ipXOsoTw@mail.gmail.com> <5009DB2A.7070408@gentoo.org> <500A13A6.7030503@gentoo.org> <alpine.BSF.2.00.1207211014481.1535@wojtek.tensor.gdynia.pl> <500B795B.7000307@gentoo.org> <63653b2570964cb995f7191fabdb52c8@HUBCAS2.cs.stonybrook.edu>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7F1E5AD08EEA7A960EB00674 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 07/22/2012 03:19 AM, Wojciech Puchar wrote: >> You are right. It is not capped at that speed: >> >> root@freebsd:/root # dd if=3D/dev/zero of=3D/dev/da1 bs=3D16384 count=3D= 262144 >> >> >> >> 262144+0 records in >> 262144+0 records out >> 4294967296 bytes transferred in 615.840721 secs (6974153 bytes/sec) >> >> > you did test da1 while dmesg are about da0? >=20 > is it OK and da1 is another qemu-kvm vdisk? >=20 > If so, check >=20 > dd if=3D/dev/zero of=3D/dev/da1 bs=3D512 count=3D256k >=20 > and compare speed. >=20 > i bet at something near 250kB/s and i think it is long I/O service=20 > pathlength in qemu-kvm SCSI device simulator. >=20 > Just my bet i don't run FreeBSD on any VM (as opposed to running Window= s=20 > under FreeBSD in VBox) >=20 > check out how much CPU is used on the host side when you do that test. > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.o= rg" The test was on da1, but that does not explain how Linux manages to get over 100MB/s when writing to a file on ext4. I will do some more comprehensive tests as soon as I find time. --------------enig7F1E5AD08EEA7A960EB00674 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBAgAGBQJQD8lIAAoJECDuEZm+6Exk+DsP/jvqXUDEBlglCP79abNDJ3zy F/Au0LCk8ylgQwvNbS5vRJy0lMpfYZKjywNh/8A84b9kfqcshmpFZdwoiOyM/Z5X i3iuQTwwbXIQ91C53fE9wSfK2bmoXBM+zbLPMmaLw1qklk9H8/JGnAVT8UvyS+SW lAVUVO25NDsKoJT6Yh/S1xqdaUGpGIsjBqKxl6S4ZvWuamb7ZHoHUuRithwRWRRF GzfKky1FZ/gTRC5TLXXgaaXN9xpDz0O7mmCYvmNI/2JE9L9LgxP+zq5edpyIJ1ch bOcmjegbJ1i77D+6v+8kPg6HLFw97MUJqGczq1IbEcliWlWBBjlBHe0hwoOi2ARD gD4/v7OKmnOJb2dZEthOI/EF6bwWEE6EWhmT+/XRf3oGrgxf6ZtTmK9hLu95wDbn OTLQyNPHB88yJCLsyHuDKut9Ny7pph3hDBQHACPmy9MmQHvW8/RIIORBIfGz+T5/ ddcnLno4HXkIRtkewmiJUApkjUq+fSdchEYu2DzrgKvNvWkAP/vSBNYq6IWnD3Nf P8NPoADV/VxB2rQwvrTqJboRbH7bXik2fqbAMerUHmek0BcszS0P6o0Xr2YEEK+R uD3ov/Yb9332HD0aBsMiAWrn08eiFiz9diSf7Jgwlm/2AvXFW5GYmBznuSENP6oK mku1FyTDw336awa/sWea =V+nb -----END PGP SIGNATURE----- --------------enig7F1E5AD08EEA7A960EB00674--
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