Date: Mon, 1 Sep 2008 18:46:21 +0400 (MSD) From: Anton Yuzhaninov <citrin@citrin.ru> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/127024: Problem with unix sockets garbage collector Message-ID: <20080901144621.8751589A47D@mx22.rambler.ru> Resent-Message-ID: <200809011510.m81FA2WT093644@freefall.freebsd.org>
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>Number: 127024
>Category: kern
>Synopsis: Problem with unix sockets garbage collector
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Mon Sep 01 15:10:00 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator: Anton Yuzhaninov
>Release: FreeBSD 7.0-STABLE amd64
>Organization:
Rambler
>Environment:
System: FreeBSD mx22.rambler.ru 7.0-STABLE FreeBSD 7.0-STABLE #1: Fri Jun 27 16:59:59 MSD 2008 root@mx22.rambler.ru:/usr/obj/usr/src/sys/MAIL amd64
Problem occurs on SMP boxes, when unix sockets used under high load.
In our case it is server with postfix MTA, where unix sockets used for IPC.
>Description:
1. Normal work (after reboot):
thread taskq in top is about 0.00% WCPU
sysctl net.local.inflight is almost always zero.
sysctl net.local.taskcount value increased rarely.
2. After several days of work thread taskq starts to eat all available CPU:
1684 processes:26 running, 1639 sleeping, 19 waiting
CPU states: 6.7% user, 0.0% nice, 54.5% system, 1.1% interrupt, 37.7% idle
Mem: 1332M Active, 1903M Inact, 505M Wired, 118M Cache, 214M Buf, 76M Free
Swap: 2060M Total, 2060M Free
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
9 root 1 8 - 0K 16K CPU1 1 536:07 100.00% thread taskq
12 root 1 171 ki31 0K 16K RUN 0 53.5H 64.06% idle: cpu0
11 root 1 171 ki31 0K 16K RUN 1 50.3H 14.26% idle: cpu1
sysctl net.local.inflight value is always less then 0 (I see values from -1 to -4).
sysctl net.local.taskcount values increased with high rate (about 100 per second).
It seems to be some race in unix sockets code, because on uniprocessor box we can't repeat this.
>How-To-Repeat:
Run postfix MTA on high loaded mail server (> 100 connects per second) with 6-stable or 7-stable (SMP).
Problem should occurs after several days (weeks) of uptime.
>Fix:
Not known yet.
May be in 8-current this problem fixed, but we can't run 8-current on this hardware.
>Release-Note:
>Audit-Trail:
>Unformatted:
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