On Sun, Jul 14, 2002 at 10:22:19AM +0530, Dipankar Sarma wrote:
> Even if you replace timemr_bh() with a tasklet, you still need
> to take the global_bh_lock to ensure that timers don't race with
> single-threaded BH processing in drivers. I wrote this patch [included]
> to get rid of timer_bh in Ingo's smptimers, but it acquires
> global_bh_lock as well as net_bh_lock, the latter to ensure
> that some older protocol code that expected serialization of
> NET_BH and timers work correctly (see deliver_to_old_ones()).
> They need to be cleaned up too.
> My patch of course was experimental to see what is needed to
> get rid of timer_bh. It needs some cleanup itself ;-)
It turns out those profiling results are total garbage. oprofile
hit counts during the tbench 1024 run with smptimers-X1 on the 16-way
16GB NUMA-Q follow:
c020249d 43051806 73.9493 .text.lock.dev
c0196750 2138900 3.67395 csum_partial_copy_generic
c020090c 1454023 2.49755 netif_rx
c0200e78 1237550 2.12572 process_backlog
c0200480 1083695 1.86144 dev_queue_xmit
c0120bf8 1013839 1.74145 run_timer_tasklet
c0228c8c 946933 1.62653 tcp_v4_rcv
c0196920 773495 1.32862 __generic_copy_to_user
c012009c 605591 1.04021 mod_timer
c01fbe98 477906 0.820891 sock_wfree
c0218e14 392831 0.674759 tcp_recvmsg
c0112648 362804 0.623182 try_to_wake_up
c01132fc 278976 0.479192 schedule
c0136087 251550 0.432083 .text.lock.page_alloc
c0211d14 215139 0.36954 ip_queue_xmit
c021759c 205078 0.352259 tcp_sendmsg
c0220ad4 203218 0.349064 tcp_rcv_established
c0112f64 189216 0.325013 scheduler_tick
c02221a4 187313 0.321744 tcp_transmit_skb
c021f5fc 184471 0.316863 tcp_data_queue
c02189a8 163828 0.281404 tcp_data_wait
c01dd820 139310 0.23929 loopback_xmit
c01fcfcc 137241 0.235736 skb_release_data
I'll follow up with the "before" profile next.
Cheers,
Bill
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This archive was generated by hypermail 2b29 : Tue Jul 23 2002 - 22:00:25 EST