Re: [patch] voluntary-preempt-2.6.9-rc2-mm1-S3

From: Lee Revell
Date: Wed Sep 22 2004 - 14:11:08 EST


On Wed, 2004-09-22 at 06:33, Ingo Molnar wrote:
> http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.9-rc2-mm1-S3

The rt_garbage_collect latency is back:

preemption latency trace v1.0.7 on 2.6.9-rc2-mm1-VP-S3
-------------------------------------------------------
latency: 2040 us, entries: 2321 (2321) | [VP:1 KP:1 SP:1 HP:1 #CPUS:1]
-----------------
| task: ksoftirqd/0/2, uid:0 nice:0 policy:0 rt_prio:0
-----------------
=> started at: netif_receive_skb+0x6a/0x1d0
=> ended at: netif_receive_skb+0x125/0x1d0
=======>
00000001 0.000ms (+0.001ms): netif_receive_skb (process_backlog)
00000001 0.001ms (+0.000ms): packet_rcv_spkt (netif_receive_skb)
00000001 0.002ms (+0.000ms): skb_clone (packet_rcv_spkt)
00000001 0.002ms (+0.001ms): kmem_cache_alloc (skb_clone)
00000001 0.004ms (+0.001ms): memcpy (skb_clone)
00000001 0.006ms (+0.001ms): strlcpy (packet_rcv_spkt)
00000002 0.007ms (+0.003ms): sk_run_filter (packet_rcv_spkt)
00000001 0.011ms (+0.000ms): __kfree_skb (packet_rcv_spkt)
00000001 0.012ms (+0.000ms): kfree_skbmem (__kfree_skb)
00000001 0.012ms (+0.000ms): skb_release_data (kfree_skbmem)
00000001 0.012ms (+0.000ms): kmem_cache_free (kfree_skbmem)
00000001 0.013ms (+0.001ms): ip_rcv (netif_receive_skb)
00000001 0.015ms (+0.000ms): ip_route_input (ip_rcv)
00000001 0.015ms (+0.003ms): rt_hash_code (ip_route_input)
00000001 0.019ms (+0.001ms): ip_route_input_slow (ip_rcv)
00000001 0.021ms (+0.001ms): rt_hash_code (ip_route_input_slow)
00000001 0.022ms (+0.002ms): fn_hash_lookup (ip_route_input_slow)
00000002 0.024ms (+0.002ms): fib_semantic_match (fn_hash_lookup)
00000001 0.027ms (+0.000ms): fib_validate_source (ip_route_input_slow)
00000001 0.028ms (+0.001ms): fn_hash_lookup (fib_validate_source)
00000001 0.029ms (+0.001ms): fn_hash_lookup (fib_validate_source)
00000002 0.031ms (+0.001ms): fib_semantic_match (fn_hash_lookup)
00000001 0.032ms (+0.000ms): __fib_res_prefsrc (fib_validate_source)
00000001 0.033ms (+0.002ms): inet_select_addr (__fib_res_prefsrc)
00000001 0.035ms (+0.000ms): dst_alloc (ip_route_input_slow)
00000001 0.036ms (+0.002ms): rt_garbage_collect (dst_alloc)
00000102 0.039ms (+0.001ms): rt_may_expire (rt_garbage_collect)
00000101 0.040ms (+0.000ms): local_bh_enable (rt_garbage_collect)
00000102 0.041ms (+0.001ms): rt_may_expire (rt_garbage_collect)
00000101 0.042ms (+0.000ms): local_bh_enable (rt_garbage_collect)
00000102 0.043ms (+0.000ms): rt_may_expire (rt_garbage_collect)
00000101 0.044ms (+0.000ms): local_bh_enable (rt_garbage_collect)
00000102 0.045ms (+0.001ms): rt_may_expire (rt_garbage_collect)
00000102 0.046ms (+0.001ms): rt_may_expire (rt_garbage_collect)
00000101 0.047ms (+0.000ms): local_bh_enable (rt_garbage_collect)
00000102 0.048ms (+0.001ms): rt_may_expire (rt_garbage_collect)

[these 2 repeat hundreds of times]

00000101 1.875ms (+0.000ms): local_bh_enable (rt_garbage_collect)
00000102 1.876ms (+0.000ms): rt_may_expire (rt_garbage_collect)
00000102 1.877ms (+0.000ms): rt_may_expire (rt_garbage_collect)
00000101 1.877ms (+0.000ms): local_bh_enable (rt_garbage_collect)
00000102 1.878ms (+0.000ms): rt_may_expire (rt_garbage_collect)
00000102 1.879ms (+0.000ms): rt_may_expire (rt_garbage_collect)
00000101 1.880ms (+0.001ms): local_bh_enable (rt_garbage_collect)
00000001 1.881ms (+0.001ms): kmem_cache_alloc (dst_alloc)
00000001 1.882ms (+0.003ms): cache_alloc_refill (kmem_cache_alloc)

[some other stuff]

Lee

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