|
shmdt的情况:
$ strace -fTr -o /tmp/a2.txt sqlplus -s -l / as sysdba <<<quit
$ awk '{print $2}' /tmp/a2.txt | sort -nr | head
5.041521
0.287119
0.064745
0.008298
0.006386
0.004288
0.004272
0.001319
0.000982
0.000978
--//查看a2.txt
3366 0.000067 stat("/u01/app/oracle/product/11.2.0.4/dbhome_1/lib", {st_mode=S_IFDIR|0755, st_size=12288, ...}) = 0 <0.000025>
3366 0.000112 chdir("/u01/app/oracle/product/11.2.0.4/dbhome_1/dbs") = 0 <0.000027>
3366 5.041521 mmap(NULL, 143360, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4c2c0b3000 <0.000048>
3366 0.000407 mmap(NULL, 143360, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4c2c090000 <0.000015>
3366 0.000127 mmap(NULL, 143360, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4c2c06d000 <0.000013>
3366 0.000218 getcwd("/u01/app/oracle/product/11.2.0.4/dbhome_1/dbs"..., 256) = 46 <0.000016>
3366 0.000087 access("/etc/intchg.ora", F_OK) = -1 ENOENT (No such file or directory) <0.000019>
...
--//也就是在chdir调用与mmap调用之间有5秒不知道在干什么?(chdir 仅仅需要0.000027秒).strace看不出来!!
--//如果你使用top -u oracle观察,你可以发现RES字段不断在增加,接近SGA设置.我的感觉就是在这里建立pagetables的过程.
$ cat aa.sql
host sleep 1
quit
$ cat a.sh
#! /bin/bash
export ORACLE_SID=xxxx
sqlplus -s -l / as sysdba @ aa.sql &
a=$(($!+2))
top -p $a -d 1 -b
$ . a.sh | tee /tmp/aa.txt
...
--//按ctrl+c中断.
$ grep PID /tmp/aa.txt | head -1; egrep 'oracle' /tmp/aa.txt
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
8498 oracle 20 0 20.2g 1.5g 1.5g R 93.9 1.2 0:00.47 oracle
8498 oracle 20 0 20.2g 5.8g 5.8g R 99.7 4.6 0:01.47 oracle
8498 oracle 20 0 20.2g 10g 10g R 99.8 8.4 0:02.47 oracle
8498 oracle 20 0 20.2g 15g 15g R 99.8 12.2 0:03.47 oracle
--//sleep 1
8498 oracle 20 0 20.2g 19g 19g S 95.9 15.7 0:04.43 oracle
8498 oracle 20 0 20.2g 19g 19g S 0.0 15.7 0:04.43 oracle
8498 oracle 20 0 20.0g 19g 19g R 1.0 15.6 0:04.44 oracle
--//你可以发现RES,SHR都在增加,CPU使用率在9X%,感觉11g版本在设置pre_page_sga=true下有问题.
--//大致定位时间定位在建立pagetables的过程.
5.改用hugepages呢?
$ grep -i page /proc/meminfo
AnonPages: 244144 kB
PageTables: 11508 kB
AnonHugePages: 0 kB
HugePages_Total: 26000
HugePages_Free: 15800
HugePages_Rsvd: 41
HugePages_Surp: 0
Hugepagesize: |