search for: queue_flag_nonrot

...st, but qemu and virtio > don't seem to have this. Pretty surprising! Is it called something > other than "rotational"? > I'm not sure if we need to add this property in QEMU, but in Linux I found these flags (include/linux/blkdev.h) for the block queues: #define QUEUE_FLAG_NONROT 6 /* non-rotational device (SSD) */ #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ xen-blkfront driver is the only one that sets the QUEUE_FLAG_VIRT, should we do the same in the virtio-blk driver regardless of the backend? Thanks, Stefano

...st, but qemu and virtio > don't seem to have this. Pretty surprising! Is it called something > other than "rotational"? > I'm not sure if we need to add this property in QEMU, but in Linux I found these flags (include/linux/blkdev.h) for the block queues: #define QUEUE_FLAG_NONROT 6 /* non-rotational device (SSD) */ #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ xen-blkfront driver is the only one that sets the QUEUE_FLAG_VIRT, should we do the same in the virtio-blk driver regardless of the backend? Thanks, Stefano

...rising! Is it called something > > > other than "rotational"? > > > > > > > I'm not sure if we need to add this property in QEMU, but in Linux > > I found these flags (include/linux/blkdev.h) for the block queues: > > > > #define QUEUE_FLAG_NONROT 6 /* non-rotational device (SSD) */ > > #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ > > > > xen-blkfront driver is the only one that sets the QUEUE_FLAG_VIRT, > > should we do the same in the virtio-blk driver regardless of the backend? > > T...

...9;t seem to have this. Pretty surprising! Is it called something > > other than "rotational"? > > > > I'm not sure if we need to add this property in QEMU, but in Linux > I found these flags (include/linux/blkdev.h) for the block queues: > > #define QUEUE_FLAG_NONROT 6 /* non-rotational device (SSD) */ > #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ > > xen-blkfront driver is the only one that sets the QUEUE_FLAG_VIRT, > should we do the same in the virtio-blk driver regardless of the backend? The ability to control this fla...

...AG_VIRT caueses major performance regressions for Fedora users: https://bugzilla.redhat.com/show_bug.cgi?id=509383 https://bugzilla.redhat.com/show_bug.cgi?id=505695 while I can't reproduce those extreme regressions myself I think the flag is wrong. Rationale: QUEUE_FLAG_VIRT expands to QUEUE_FLAG_NONROT which casus the queue unplugged immediately. This is not a good behaviour for at least qemu and kvm where we do have significant overhead for every I/O operations. Even with all the latested speeups (native AIO, MSI support, zero copy) we can only get native speed for up to 128kb I/O re...

...AG_VIRT caueses major performance regressions for Fedora users: https://bugzilla.redhat.com/show_bug.cgi?id=509383 https://bugzilla.redhat.com/show_bug.cgi?id=505695 while I can't reproduce those extreme regressions myself I think the flag is wrong. Rationale: QUEUE_FLAG_VIRT expands to QUEUE_FLAG_NONROT which casus the queue unplugged immediately. This is not a good behaviour for at least qemu and kvm where we do have significant overhead for every I/O operations. Even with all the latested speeups (native AIO, MSI support, zero copy) we can only get native speed for up to 128kb I/O re...

...AG_VIRT caueses major performance regressions for Fedora users: https://bugzilla.redhat.com/show_bug.cgi?id=509383 https://bugzilla.redhat.com/show_bug.cgi?id=505695 while I can't reproduce those extreme regressions myself I think the flag is wrong. Rationale: QUEUE_FLAG_VIRT expands to QUEUE_FLAG_NONROT which casus the queue unplugged immediately. This is not a good behaviour for at least qemu and kvm where we do have significant overhead for every I/O operations. Even with all the latested speeups (native AIO, MSI support, zero copy) we can only get native speed for up to 128kb I/O re...

...AG_VIRT caueses major performance regressions for Fedora users: https://bugzilla.redhat.com/show_bug.cgi?id=509383 https://bugzilla.redhat.com/show_bug.cgi?id=505695 while I can't reproduce those extreme regressions myself I think the flag is wrong. Rationale: QUEUE_FLAG_VIRT expands to QUEUE_FLAG_NONROT which casus the queue unplugged immediately. This is not a good behaviour for at least qemu and kvm where we do have significant overhead for every I/O operations. Even with all the latested speeups (native AIO, MSI support, zero copy) we can only get native speed for up to 128kb I/O re...

...sions for Fedora users: https://bugzilla.redhat.com/show_bug.cgi?id=509383 https://bugzilla.redhat.com/show_bug.cgi?id=505695 while I can't reproduce those extreme regressions myself I think the flag is wrong. Rationale: QUEUE_FLAG_VIRT expands to QUEUE_FLAG_NONROT which casus the queue unplugged immediately. This is not a good behaviour for at least qemu and kvm where we do have significant overhead for every I/O operations. Even with all the latested speeups (native AIO, MSI support, zero copy) we can only get native speed for up t...

...sions for Fedora users: https://bugzilla.redhat.com/show_bug.cgi?id=509383 https://bugzilla.redhat.com/show_bug.cgi?id=505695 while I can't reproduce those extreme regressions myself I think the flag is wrong. Rationale: QUEUE_FLAG_VIRT expands to QUEUE_FLAG_NONROT which casus the queue unplugged immediately. This is not a good behaviour for at least qemu and kvm where we do have significant overhead for every I/O operations. Even with all the latested speeups (native AIO, MSI support, zero copy) we can only get native speed for up t...

Hi all, These 2 patches added virtio-nvme to kernel and qemu, basically modified from virtio-blk and nvme code. As title said, request for your comments. Play it in Qemu with: -drive file=disk.img,format=raw,if=none,id=D22 \ -device virtio-nvme-pci,drive=D22,serial=1234,num_queues=4 The goal is to have a full NVMe stack from VM guest(virtio-nvme) to host(vhost_nvme) to LIO NVMe-over-fabrics

Hi all, These 2 patches added virtio-nvme to kernel and qemu, basically modified from virtio-blk and nvme code. As title said, request for your comments. Play it in Qemu with: -drive file=disk.img,format=raw,if=none,id=D22 \ -device virtio-nvme-pci,drive=D22,serial=1234,num_queues=4 The goal is to have a full NVMe stack from VM guest(virtio-nvme) to host(vhost_nvme) to LIO NVMe-over-fabrics

...AG_BIDI 7 /* queue supports bidi requests */ #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */ #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */ #define QUEUE_FLAG_FAIL_IO 10 /* fake timeout */ #define QUEUE_FLAG_STACKABLE 11 /* supports request stacking */ #define QUEUE_FLAG_NONROT 12 /* non-rotational device (SSD) */ #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ #define QUEUE_FLAG_IO_STAT 13 /* do IO stats */ #define QUEUE_FLAG_DISCARD 14 /* supports DISCARD */ #define QUEUE_FLAG_NOXMERGES 15 /* No extended merges */ #define QUEUE_FLAG...

...AG_BIDI 7 /* queue supports bidi requests */ #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */ #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */ #define QUEUE_FLAG_FAIL_IO 10 /* fake timeout */ #define QUEUE_FLAG_STACKABLE 11 /* supports request stacking */ #define QUEUE_FLAG_NONROT 12 /* non-rotational device (SSD) */ #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ #define QUEUE_FLAG_IO_STAT 13 /* do IO stats */ #define QUEUE_FLAG_DISCARD 14 /* supports DISCARD */ #define QUEUE_FLAG_NOXMERGES 15 /* No extended merges */ #define QUEUE_FLAG...