From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [Bug #11308] tbench regression on each kernel release from 2.6.22 -> 2.6.28 Date: Mon, 17 Nov 2008 11:39:36 -0800 (PST) Message-ID: <20081117.113936.81699150.davem@davemloft.net> References: <20081117182320.GA26844@elte.hu> <20081117184951.GA5585@elte.hu> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081117184951.GA5585-X9Un+BFzKDI@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: mingo-X9Un+BFzKDI@public.gmane.org Cc: torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, dada1-fPLkHRcR87vqlBn2x/YWAg@public.gmane.org, rjw-KKrjLPT3xs0@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, efault-Mmb7MZpHnFY@public.gmane.org, a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org, shemminger-ZtmgI6mnKB3QT0dZR+AlfA@public.gmane.org From: Ingo Molnar Date: Mon, 17 Nov 2008 19:49:51 +0100 > > * Ingo Molnar wrote: > > 4> The place for the sock_rfree() hit looks a bit weird, and i'll > > investigate it now a bit more to place the real overhead point > > properly. (i already mapped the test-bit overhead: that comes from > > napi_disable_pending()) > > ok, here's a new set of profiles. (again for tbench 64-thread on a > 16-way box, with v2.6.28-rc5-19-ge14c8bf and with the kernel config i > posted before.) Again, do a non-NMI profile and the top (at least for me) looks like this: samples % app name symbol name 473 6.3928 vmlinux finish_task_switch 349 4.7169 vmlinux tcp_v4_rcv 327 4.4195 vmlinux U3copy_from_user 322 4.3519 vmlinux tl0_linux32 178 2.4057 vmlinux tcp_ack 170 2.2976 vmlinux tcp_sendmsg 167 2.2571 vmlinux U3copy_to_user That tcp_v4_rcv() hit is %98 on the wake_up() call it does.