Date: Mon, 2 Jan 2012 20:35:31 -0800 From: Vijay Singh <vijju.singh@gmail.com> To: freebsd-net@freebsd.org Subject: Use of spinlocks for TCP callouts Message-ID: <CALCNsJRgboHoe7ec-7MQ4U2rOyO%2BbzodeicgMPLZyp2wLvwvAw@mail.gmail.com>
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I have see the following call sequence in profiles:
called/total parents
index %time self descendents called+self name index
called/total children
0.02 1.14 3822699/7559737 tcp_do_segment
[154] 0.5 0.03 2.26 7559737 callout_reset_on
2.19 0.02 7573352/94883048 spinlock_exit
0.01 0.04 7573352/11975031 callout_lock
It is my perception that spinlocks are expensive. Since general TCP
locks are sleep mutexes, would there be any merit in building a TCP
callout facility using sleep mutexes? I can hack something up and
share here but wanted to check if people know of an existing facility
that might be used here?
-vijay
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