On Sat, 2015-11-21 at 14:11 +0100, Paolo Bonzini wrote: > > On 20/11/2015 01:20, Ming Lin wrote: > > One improvment could be to use google's NVMe vendor extension that > > I send in another thread, aslo here: > > https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=nvme-google-ext > > > > Qemu side: > > http://www.minggr.net/cgit/cgit.cgi/qemu/log/?h=vhost-nvme.0 > > Kernel side also here: > > https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=vhost-nvme.0 > > How much do you get with vhost-nvme plus vendor extension, compared to > 190 MB/s for QEMU? There is still some bug. I'll update. > > Note that in all likelihood, QEMU can actually do better than 190 MB/s, > and gain more parallelism too, by moving the processing of the > ioeventfds to a separate thread. This is similar to > hw/block/dataplane/virtio-blk.c. > > It's actually pretty easy to do. Even though > hw/block/dataplane/virtio-blk.c is still using some old APIs, all memory > access in QEMU is now thread-safe. I have pending patches for 2.6 that > cut that file down to a mere 200 lines of code, NVMe would probably be > about the same. Is there a git tree for your patches? Did you mean some pseduo code as below? 1. need a iothread for each cq/sq? 2. need a AioContext for each cq/sq? hw/block/nvme.c | 32 ++++++++++++++++++++++++++++++-- hw/block/nvme.h | 8 ++++++++ 2 files changed, 38 insertions(+), 2 deletions(-) diff --git a/hw/block/nvme.c b/hw/block/nvme.c index f27fd35..fed4827 100644 --- a/hw/block/nvme.c +++ b/hw/block/nvme.c @@ -28,6 +28,8 @@ #include "sysemu/sysemu.h" #include "qapi/visitor.h" #include "sysemu/block-backend.h" +#include "sysemu/iothread.h" +#include "qom/object_interfaces.h" #include "nvme.h" @@ -558,9 +560,22 @@ static void nvme_init_cq_eventfd(NvmeCQueue *cq) uint16_t offset = (cq->cqid*2+1) * (4 << NVME_CAP_DSTRD(n->bar.cap)); event_notifier_init(&cq->notifier, 0); - event_notifier_set_handler(&cq->notifier, nvme_cq_notifier); memory_region_add_eventfd(&n->iomem, 0x1000 + offset, 4, false, 0, &cq->notifier); + + object_initialize(&cq->internal_iothread_obj, + sizeof(cq->internal_iothread_obj), + TYPE_IOTHREAD); + user_creatable_complete(OBJECT(&cq->internal_iothread_obj), &error_abort); + cq->iothread = &cq->internal_iothread_obj; + cq->ctx = iothread_get_aio_context(cq->iothread); + //Question: Need a conf.blk for each cq/sq??? + //blk_set_aio_context(cq->conf->conf.blk, cq->ctx); + + aio_context_acquire(cq->ctx); + aio_set_event_notifier(cq->ctx, &cq->notifier, true, + nvme_cq_notifier); + aio_context_release(cq->ctx); } static void nvme_sq_notifier(EventNotifier *e) @@ -578,9 +593,22 @@ static void nvme_init_sq_eventfd(NvmeSQueue *sq) uint16_t offset = sq->sqid * 2 * (4 << NVME_CAP_DSTRD(n->bar.cap)); event_notifier_init(&sq->notifier, 0); - event_notifier_set_handler(&sq->notifier, nvme_sq_notifier); memory_region_add_eventfd(&n->iomem, 0x1000 + offset, 4, false, 0, &sq->notifier); + + object_initialize(&sq->internal_iothread_obj, + sizeof(sq->internal_iothread_obj), + TYPE_IOTHREAD); + user_creatable_complete(OBJECT(&sq->internal_iothread_obj), &error_abort); + sq->iothread = &sq->internal_iothread_obj; + sq->ctx = iothread_get_aio_context(sq->iothread); + //Question: Need a conf.blk for each cq/sq??? + //blk_set_aio_context(sq->conf->conf.blk, sq->ctx); + + aio_context_acquire(sq->ctx); + aio_set_event_notifier(sq->ctx, &sq->notifier, true, + nvme_sq_notifier); + aio_context_release(sq->ctx); } static uint16_t nvme_set_db_memory(NvmeCtrl *n, const NvmeCmd *cmd) diff --git a/hw/block/nvme.h b/hw/block/nvme.h index 608f202..171ee0b 100644 --- a/hw/block/nvme.h +++ b/hw/block/nvme.h @@ -667,6 +667,10 @@ typedef struct NvmeSQueue { * do not go over this value will not result in MMIO writes (but will * still write the tail pointer to the "db_addr" location above). */ uint64_t eventidx_addr; + + IOThread *iothread; + IOThread internal_iothread_obj; + AioContext *ctx; EventNotifier notifier; } NvmeSQueue; @@ -690,6 +694,10 @@ typedef struct NvmeCQueue { * do not go over this value will not result in MMIO writes (but will * still write the head pointer to the "db_addr" location above). */ uint64_t eventidx_addr; + + IOThread *iothread; + IOThread internal_iothread_obj; + AioContext *ctx; EventNotifier notifier; } NvmeCQueue; > > Paolo _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
