From: Tim Chen <tim.c.chen@linux.intel.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>, Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH net-next-2.6] inetpeer: lower false sharing effect
Date: Thu, 09 Jun 2011 17:03:55 -0700 [thread overview]
Message-ID: <1307664235.17300.44.camel@schen9-DESK> (raw)
In-Reply-To: <1307600810.3980.85.camel@edumazet-laptop>
On Thu, 2011-06-09 at 08:26 +0200, Eric Dumazet wrote:
> Profiles show false sharing in addr_compare() because refcnt/dtime
> changes dirty the first inet_peer cache line, where are lying the keys
> used at lookup time. If many cpus are calling inet_getpeer() and
> inet_putpeer(), or need frag ids, addr_compare() is in 2nd position in
> "perf top".
>
I've applied both inetpeer patches. I also no longer have inet_getpeer
and inet_putpeer and addr_compare in my profile. Instead, neighbor
lookup is now dominant. See profile below.
When I retest with original 3.0-rc2 kernel, inet_putpeer no longer shows
up, wonder if dst->peer was not set for some reason.
Tim
- 27.06% memcached [kernel.kallsyms] [k] atomic_add_unless.clone.34
- atomic_add_unless.clone.34
- 99.97% neigh_lookup
__neigh_lookup_errno.clone.17
arp_bind_neighbour
rt_intern_hash
__ip_route_output_key
ip_route_output_flow
udp_sendmsg
inet_sendmsg
__sock_sendmsg
sock_sendmsg
__sys_sendmsg
sys_sendmsg
system_call_fastpath
__sendmsg
- 13.33% memcached [kernel.kallsyms] [k] atomic_dec_and_test
- atomic_dec_and_test
- 99.89% dst_destroy
- dst_release
- 98.12% skb_dst_drop.clone.55
dev_hard_start_xmit
+ sch_direct_xmit
+ 1.88% skb_release_head_state
- 3.26% memcached [kernel.kallsyms] [k] do_raw_spin_lock
- do_raw_spin_lock
- 92.24% _raw_spin_lock
+ 41.39% sch_direct_xmit
next prev parent reply other threads:[~2011-06-10 0:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-09 6:26 [PATCH net-next-2.6] inetpeer: lower false sharing effect Eric Dumazet
2011-06-09 6:31 ` David Miller
2011-06-10 0:03 ` Tim Chen [this message]
2011-06-10 3:43 ` David Miller
2011-06-10 4:47 ` Eric Dumazet
2011-06-10 22:33 ` Tim Chen
2011-06-11 0:54 ` Changli Gao
2011-06-11 4:54 ` Eric Dumazet
2011-06-11 6:17 ` Changli Gao
2011-06-11 7:09 ` Andi Kleen
2011-06-10 4:31 ` Eric Dumazet
2011-06-10 17:05 ` Tim Chen
2011-06-10 17:17 ` Eric Dumazet
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