1, without bypass coroutine, with coroutine resize, througput: 101K
   2.76%  qemu-system-x86  libpthread-2.15.so       [.] 0x000000000000eccd
   2.74%  qemu-system-x86  qemu-system-x86_64       [.] vring_pop
   2.64%  qemu-system-x86  libc-2.15.so             [.] __memcpy_ssse3_back
   2.15%  qemu-system-x86  qemu-system-x86_64       [.] memory_region_find
   1.62%  qemu-system-x86  [kernel.kallsyms]        [k] do_blockdev_direct_IO
   1.61%  qemu-system-x86  [kernel.kallsyms]        [k] vmx_vcpu_run
   1.60%  qemu-system-x86  qemu-system-x86_64       [.] cmp_flatrange_addr
   1.59%  qemu-system-x86  [kernel.kallsyms]        [k] vcpu_enter_guest
   1.50%  qemu-system-x86  [kernel.kallsyms]        [k] put_compound_page.part.22
   1.35%  qemu-system-x86  libc-2.15.so             [.] bsearch
   1.30%  qemu-system-x86  [kernel.kallsyms]        [k] __get_page_tail
   1.28%  qemu-system-x86  libpthread-2.15.so       [.] pthread_mutex_lock
   1.26%  qemu-system-x86  libpthread-2.15.so       [.] pthread_mutex_unlock
   1.21%  qemu-system-x86  [kernel.kallsyms]        [k] _raw_spin_lock_irqsave
   1.03%  qemu-system-x86  [kernel.kallsyms]        [k] _raw_spin_lock
   0.84%  qemu-system-x86  qemu-system-x86_64       [.] address_space_get_flatview.isra.13
   0.80%  qemu-system-x86  qemu-system-x86_64       [.] bdrv_co_do_preadv
   0.78%  qemu-system-x86  [kernel.kallsyms]        [k] _raw_spin_unlock_irqrestore
   0.78%  qemu-system-x86  qemu-system-x86_64       [.] object_unref
   0.73%  qemu-system-x86  qemu-system-x86_64       [.] bdrv_aligned_preadv
   0.70%  qemu-system-x86  qemu-system-x86_64       [.] flatview_unref
   0.70%  qemu-system-x86  qemu-system-x86_64       [.] qemu_coroutine_switch
   0.70%  qemu-system-x86  libglib-2.0.so.0.3200.4  [.] g_slice_alloc
   0.69%  qemu-system-x86  libc-2.15.so             [.] malloc
   0.67%  qemu-system-x86  qemu-system-x86_64       [.] object_ref
   0.65%  qemu-system-x86  [kernel.kallsyms]        [k] kmem_cache_alloc
   0.64%  qemu-system-x86  [kernel.kallsyms]        [k] compound_unlock_irqrestore          ▒
   0.64%  qemu-system-x86  [kernel.kallsyms]        [k] gup_huge_pmd                        ▒
   0.64%  qemu-system-x86  [kernel.kallsyms]        [k] copy_user_generic_string            ▒
   0.63%  qemu-system-x86  qemu-system-x86_64       [.] addrrange_intersection              ▒
   0.62%  qemu-system-x86  libglib-2.0.so.0.3200.4  [.] g_slice_free1                       ▒
   0.61%  qemu-system-x86  [kernel.kallsyms]        [k] paging64_walk_addr_generic          ▒
   0.60%  qemu-system-x86  libpthread-2.15.so       [.] pthread_getspecific                 ▒
   0.58%  qemu-system-x86  [kernel.kallsyms]        [k] kmem_cache_free                     ▒
   0.56%  qemu-system-x86  qemu-system-x86_64       [.] vring_map                           ▒
   0.56%  qemu-system-x86  [kernel.kallsyms]        [k] __fget                              ▒
   0.55%  qemu-system-x86  libc-2.15.so             [.] _int_free                           ▒
   0.55%  qemu-system-x86  qemu-system-x86_64       [.] addrrange_intersects                ▒
   0.55%  qemu-system-x86  [kernel.kallsyms]        [k] generic_file_aio_read               ▒
   0.52%  qemu-system-x86  [kernel.kallsyms]        [k] __blk_mq_run_hw_queue               ▒
   0.52%  qemu-system-x86  [kernel.kallsyms]        [k] __srcu_read_lock                    ▒
   0.51%  qemu-system-x86  [kernel.kallsyms]        [k] do_direct_IO                        ▒
   0.50%  qemu-system-x86  [kernel.kallsyms]        [k] account_system_time                 ▒
   0.50%  qemu-system-x86  [kernel.kallsyms]        [k] arch_local_irq_save                 ▒
   0.49%  qemu-system-x86  qemu-system-x86_64       [.] tracked_request_begin               ▒
   0.49%  qemu-system-x86  [kernel.kallsyms]        [k] native_read_tsc                     ▒
   0.48%  qemu-system-x86  [kernel.kallsyms]        [k] aio_complete                        ▒
   0.47%  qemu-system-x86  [kernel.kallsyms]        [k] __vcpu_run                          ▒
   0.45%  qemu-system-x86  qemu-system-x86_64       [.] coroutine_swap                      ▒
   0.45%  qemu-system-x86  [kernel.kallsyms]        [k] native_sched_clock                  ▒
   0.45%  qemu-system-x86  [kernel.kallsyms]        [k] blk_mq_make_request
   0.44%  qemu-system-x86  libc-2.15.so             [.] _int_malloc                         ▒
   0.43%  qemu-system-x86  [kernel.kallsyms]        [k] aio_run_iocb                        ▒
   0.43%  qemu-system-x86  qemu-system-x86_64       [.] bdrv_co_io_em                       ▒
   0.41%  qemu-system-x86  qemu-system-x86_64       [.] coroutine_get_thread_state          ▒
   0.41%  qemu-system-x86  [kernel.kallsyms]        [k] native_read_msr_safe                ▒
   0.38%  qemu-system-x86  [kernel.kallsyms]        [k] blk_rq_init                         ▒
   0.37%  qemu-system-x86  [kernel.kallsyms]        [k] generic_make_request_checks         ▒
   0.37%  qemu-system-x86  [kernel.kallsyms]        [k] __acct_update_integrals             ▒
   0.36%  qemu-system-x86  [kernel.kallsyms]        [k] io_submit_one                       ▒
   0.34%  qemu-system-x86  [kernel.kallsyms]        [k] blk_throtl_bio                      ▒
   0.34%  qemu-system-x86  libc-2.15.so             [.] __libc_siglongjmp                   ▒
   0.34%  qemu-system-x86  [kernel.kallsyms]        [k] __blk_recalc_rq_segments            ▒
   0.33%  qemu-system-x86  qemu-system-x86_64       [.] qemu_bh_schedule                    ▒
   0.33%  qemu-system-x86  qemu-system-x86_64       [.] virtio_blk_handle_request           ▒
   0.32%  qemu-system-x86  [kernel.kallsyms]        [k] _raw_spin_unlock                    ▒
   0.32%  qemu-system-x86  [kernel.kallsyms]        [k] blk_account_io_done                 ▒
   0.32%  qemu-system-x86  qemu-system-x86_64       [.] get_desc.isra.3                     ▒
   0.32%  qemu-system-x86  qemu-system-x86_64       [.] bdrv_qiov_is_aligned