> It looks like vhost is slowed down for some reason which leads to more > idle time on 4.13+VHOST_RX_BATCH=1. Appreciated if you can collect the > perf.diff on host, one for rx and one for tx. >
perf data below for the associated vhost threads, baseline=4.12, delta1=4.13, delta2=4.13+VHOST_RX_BATCH=1 Client vhost: 60.12% -11.11% -12.34% [kernel.vmlinux] [k] raw_copy_from_user 13.76% -1.28% -0.74% [kernel.vmlinux] [k] get_page_from_freelist 2.00% +3.69% +3.54% [kernel.vmlinux] [k] __wake_up_sync_key 1.19% +0.60% +0.66% [kernel.vmlinux] [k] __alloc_pages_nodemask 1.12% +0.76% +0.86% [kernel.vmlinux] [k] copy_page_from_iter 1.09% +0.28% +0.35% [vhost] [k] vhost_get_vq_desc 1.07% +0.31% +0.26% [kernel.vmlinux] [k] alloc_skb_with_frags 0.94% +0.42% +0.65% [kernel.vmlinux] [k] alloc_pages_current 0.91% -0.19% -0.18% [kernel.vmlinux] [k] memcpy 0.88% +0.26% +0.30% [kernel.vmlinux] [k] __next_zones_zonelist 0.85% +0.05% +0.12% [kernel.vmlinux] [k] iov_iter_advance 0.79% +0.09% +0.19% [vhost] [k] __vhost_add_used_n 0.74% [kernel.vmlinux] [k] get_task_policy.part.7 0.74% -0.01% -0.05% [kernel.vmlinux] [k] tun_net_xmit 0.60% +0.17% +0.33% [kernel.vmlinux] [k] policy_nodemask 0.58% -0.15% -0.12% [ebtables] [k] ebt_do_table 0.52% -0.25% -0.22% [kernel.vmlinux] [k] __alloc_skb ... 0.42% +0.58% +0.59% [kernel.vmlinux] [k] eventfd_signal ... 0.32% +0.96% +0.93% [kernel.vmlinux] [k] finish_task_switch ... +1.50% +1.16% [kernel.vmlinux] [k] get_task_policy.part.9 +0.40% +0.42% [kernel.vmlinux] [k] __skb_get_hash_symmetr +0.39% +0.40% [kernel.vmlinux] [k] _copy_from_iter_full +0.24% +0.23% [vhost_net] [k] vhost_net_buf_peek Server vhost: 61.93% -10.72% -10.91% [kernel.vmlinux] [k] raw_copy_to_user 9.25% +0.47% +0.86% [kernel.vmlinux] [k] free_hot_cold_page 5.16% +1.41% +1.57% [vhost] [k] vhost_get_vq_desc 5.12% -3.81% -3.78% [kernel.vmlinux] [k] skb_release_data 3.30% +0.42% +0.55% [kernel.vmlinux] [k] raw_copy_from_user 1.29% +2.20% +2.28% [kernel.vmlinux] [k] copy_page_to_iter 1.24% +1.65% +0.45% [vhost_net] [k] handle_rx 1.08% +3.03% +2.85% [kernel.vmlinux] [k] __wake_up_sync_key 0.96% +0.70% +1.10% [vhost] [k] translate_desc 0.69% -0.20% -0.22% [kernel.vmlinux] [k] tun_do_read.part.10 0.69% [kernel.vmlinux] [k] tun_peek_len 0.67% +0.75% +0.78% [kernel.vmlinux] [k] eventfd_signal 0.52% +0.96% +0.98% [kernel.vmlinux] [k] finish_task_switch 0.50% +0.05% +0.09% [vhost] [k] vhost_add_used_n ... +0.63% +0.58% [vhost_net] [k] vhost_net_buf_peek +0.32% +0.32% [kernel.vmlinux] [k] _copy_to_iter +0.19% +0.19% [kernel.vmlinux] [k] __skb_get_hash_symmetr +0.11% +0.21% [vhost] [k] vhost_umem_interval_tr