Re: Interpreting perf stat on netperf and netserver
From: Jean-Michel Hautbois <hidden>
Date: 2012-01-19 10:26:56
2012/1/19 Eric Dumazet [off-list ref]:
Le mercredi 18 janvier 2012 à 12:33 +0100, Jean-Michel Hautbois a écrit :quoted
The be2net driver seems to have difficulties woth IRQ affinity also, because it always uses CPU0 even if the affinity is 0-23 ! netperf result is quite good, and perf top shows : PerfTop: 689 irqs/sec kernel:99.6% us: 0.3% guest kernel: 0.0% guest us: 0.0% exact: 0.0% [1000Hz cycles], (all, 24 CPUs) ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 29.28% [kernel] [k] csum_partial 8.46% [kernel] [k] copy_user_generic_string 3.70% [be2net] [k] be_poll_rx 3.08% [be2net] [k] event_handle 2.37% [kernel] [k] irq_entries_start 2.21% [be2net] [k] be_rx_compl_get 1.65% [be2net] [k] be_post_rx_frags 1.64% [kernel] [k] __napi_complete 1.50% [kernel] [k] ip_defrag 1.35% [kernel] [k] put_page 1.34% [kernel] [k] get_page_from_freelist 1.29% [kernel] [k] __netif_receive_skb 1.16% [kernel] [k] __alloc_pages_nodemask 1.14% [kernel] [k] debug_smp_processor_id 1.08% [kernel] [k] add_preempt_count 1.06% [kernel] [k] sub_preempt_count 1.03% [be2net] [k] get_rx_page_info 1.01% [kernel] [k] alloc_pages_current Checksum calculation seems quite complex :).UDP with fragments... I guess... but cant see this in the perf top output ;) What bandwidth do you get for this cpu load ?
Yes, this was UDP fragmentation :). I had 6800Mbps for a theoretical limit of 7000Mbps (Flex 10Gbps system). JM