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=/dev/zero of=/dev/da1 bs=16384 count=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? > > is it OK and da1 is another qemu-kvm vdisk? > > If so, check > > dd if=/dev/zero of=/dev/da1 bs=512 count=256k > > and compare speed. > > i bet at something near 250kB/s and i think it is long I/O service > pathlength in qemu-kvm SCSI device simulator. > > Just my bet i don't run FreeBSD on any VM (as opposed to running Windows > under FreeBSD in VBox) > > 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-unsubscr...@freebsd.org"
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.
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