This looks like the CPU cycles are being consumed by walking one or more
very long lists of memory pieces and writing them to disk one by one.
Note the UFSStoreState::write parameter size=4096 in the backtrace for
how bit those memory pages are.
Which could happen if you cached a very big object in cache_mem and then
a random time later it needed swapping out to disk to free up memory.
It could also happen if Squid needed to suddenly swap out a large number
of smaller items to make memory space available for a large one which is
about to arrive.
So, have you configured Squid to allow very large objects (many MB or
GB) in memory storage?
Note these causes would not show up in the testing you mentioned unless
you had a very wide range of test object sizes being pumped randomly
through the proxy. A tool like web polygraph is best to test that
traffic behaviour accurately.
Amos
On 5/04/2014 1:59 a.m., a.afach wrote:
Dear all
i still have the CPU spikes even when i used
disable-strict-error-checking without using Cflags
this is the gdb backtrace while the CPU spikes
0x0051b348 in linklistPush (L=0x11853e188, p=0xce6d4300) at
list.cc:47
47 while (*L)
(gdb) backtrace
#0 0x0051b348 in linklistPush (L=0x11853e188, p=0xce6d4300) at
list.cc:47
#1 0x005a70a1 in UFSStoreState::write (this=0xb3970e28,
buf=0x11fe69ca0
!v\253r[/\307\232G\b\375`\237:\213\256^\335\373{\241%\232\363\021\071`\342\033\177a\202G\320{\323%\236K\342\243*\332\316\351\231=\360\370\313Ro=\317\262\243\315\027\351,\221\230\353Z\023\024q\QSC\036\214:M\242{@\351m\020\337Cw_\214\216\304\226\265\a\375\031\211\243V\222T\320\016\227\312-\211Sz\326^\346\230\251\327\222\n\373I\032\341\303==U\214\277\264\244\205\b1\346S=\230\215\204\245\254\312\223\066\336\230PpP\227\271\370\266;\362\226\242\036\225\235w\330\325\061\316{o_\364\021\062\351\376\062|\313\006`\357m\206FQ0\021\030C\224\004]\336\315\371\033h1\361\363\350d\366\066...,
size=4096, aOffset=-1, free_func=0x5203b0 memNodeWriteComplete(void*))
at ufs/store_io_ufs.cc:247
#2 0x00554ca0 in doPages (anEntry=optimized out) at
store_swapout.cc:160
#3 StoreEntry::swapOut (this=0x372ca10) at store_swapout.cc:279
#4 0x0054c986 in StoreEntry::invokeHandlers (this=0x372ca10) at
store_client.cc:714
#5 0x004dc1a7 in FwdState::complete (this=0xbb502b48) at
forward.cc:341
#6 0x005579a5 in ServerStateData::completeForwarding
(this=0xf8030588) at Server.cc:239
#7 0x005571bd in ServerStateData::serverComplete2
(this=0xf8030588) at Server.cc:207
#8 0x004ff3dc in HttpStateData::processReplyBody
(this=0xf8030588) at http.cc:1382
#9 0x004fd367 in HttpStateData::readReply (this=0xf8030588,
io=...) at http.cc:1161
#10 0x00503156 in JobDialerHttpStateData::dial
(this=0xde75ca50, call=...) at base/AsyncJobCalls.h:175
#11 0x00569ee4 in AsyncCall::make (this=0xde75ca20) at
AsyncCall.cc:34
#12 0x0056cb76 in AsyncCallQueue::fireNext (this=optimized
out) at AsyncCallQueue.cc:53
#13 0x0056ccf0 in AsyncCallQueue::fire (this=0x2586400) at
AsyncCallQueue.cc:39
#14 0x004d385c in EventLoop::runOnce (this=0x7fffcb3518d0) at
EventLoop.cc:130
#15 0x004d3938 in EventLoop::run (this=0x7fffcb3518d0) at
EventLoop.cc:94
#16 0x0051d35b in SquidMain (argc=optimized out,
argv=optimized out) at main.cc:1418
#17 0x0051dd83 in SquidMainSafe (argv=optimized out,
argc=optimized out) at main.cc:1176
#18 main (argc=optimized out, argv=optimized out) at main.cc:1168
any idea about what's causing the cpu spike
On 2014-03-31 16:34, Amos Jeffries wrote:
On 2014-04-01 02:10, a.afach wrote:
Dear Eliezer
these are the configure options ...
configure options: '--prefix=/usr/local/squid-3.1.19'
'--sysconfdir=/etc' '--sysconfdir=/etc/squid' '--localstatedir=/var'
'--enable-auth=basic,digest,ntlm' '--enable-removal-policies=lru,heap'
'--enable-digest-auth-helpers=password'
'--enable-basic-auth-helpers=PAM,getpwnam,NCSA,MSNT'
'--enable-external-acl-helpers=ip_user,session,unix_group'
'--enable-ntlm-auth-helpers=fakeauth'
'--enable-ident-lookups--enable-useragent-log'
'--enable-cache-digests' '--enable-delay-pools' '--enable-referer-log'
'--enable-arp-acl' '--with-pthreads' '--with-large-files'
'--enable-htcp' '--enable-carp' '--enable-follow-x-forwarded-for'
'--enable-snmp' '--enable-ssl' '--enable-storeio=ufs,diskd,aufs'
'--enable-async-io' '--enable-linux-netfilter' '--enable-epoll'
'--with-squid=/usr/squid-3.1.19' '--disable-ipv6' '--with-aio'
'--with-aio-threads=128' 'build_alias=x86_64-pc-linux-gnu'
'host_alias=x86_64-pc-linux-gnu' 'CC=x86_64-pc-linux-gnu-gcc'
'CFLAGS=-O2 -pipe -m64 -mtune=generic' 'LDFLAGS=-Wl,-O1
-Wl,--as-needed' 'CXXFLAGS=' '--cache-file=/dev/null' '--srcdir=.'
Some more reasons to upgrade:
* --disable-strict-error-checking avoids issues on Gentoo with -Werror
* CFLAGS affects the
