vBulletin Search Engine Optimization
This is a discussion on 100% CPU usage with vBSEO within the Troubleshooting forums, part of the vBSEO SEO Plugin category; Summary: Two vBulletin web hosting forums running as virtual hosts in a VPS environment on high-performance hardware. Noted drastic change ...
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#1
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| 100% CPU usage with vBSEO Summary: Two vBulletin web hosting forums running as virtual hosts in a VPS environment on high-performance hardware. Noted drastic change in CPU load most requests on vBSEO forum after installing vBSEO (performance on other forum has not changed). Environment:
Sites: Both virtual hosts are relatively low-traffic (<2000 visits/day) and neither had any performance issues prior to the installation of vBSEO.
Full description of the issue: Use of this plug-in has consistently caused Apache processes to consume inordinate CPU time (generally reaches 100% for the duration of requests served by vBSEO). Depending upon the page which is requested, load times average between a minimum of 9 seconds (index) to 18 seconds (subforum index). Subforum pages which display many links demonstrate the worst performance. I believe that this issue may be related to the lack of caching a threadid => CRU name lookup. I really would not care if it takes up a few MB of memory, have plenty to go around. CPU time comes at a premium and 100% CPU load on a core for 10-20 seconds per page request is unacceptable for the user experience and system stability. Action taken: 1) Installed vBSEO at forums.vpslink.com, enabled rewrite rules and added directives to httpd.conf 2) Noted performance issues immediately, no corroborating Apache or PHP errors 3) Installed and configured XCache (see configuration below) XCache Configuration: Code: xcache.shm_scheme = "mmap" xcache.size = 64M xcache.count = 1 xcache.slots = 8K xcache.ttl = 0 xcache.gc_interval = 0 xcache.var_size = 16M xcache.var_count = 4 xcache.var_slots = 8K xcache.var_ttl = 0 xcache.var_maxttl = 0 xcache.var_gc_interval = 300 xcache.test = Off xcache.readonly_protection = Off xcache.mmap_path = "/tmp/xcache" xcache.coredump_directory = "" xcache.cacher = On xcache.stat = On xcache.optimizer = Off xcache.coverager = Off xcache.coveragedump_directory = "" Last edited by danlefree; 07-09-2008 at 08:48 PM. Reason: Minor edits |
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#2
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i've had nothing but problems with xcache on my box. Xcache: Server, ssh, putty...: SkeyMedia I currently run eAccelerator with good results. otherwise, have a look through these: vBSEO Optimization Tips |
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#3
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Perhaps it's xcache actually running up your usage? Have you tried any other PHP accelerators? |
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#4
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I'd expect a series of preg_replace() calls to bog things down a bit, and I was surprised that vBSEO did not include a threadid => CRU lookup array or a series of constant definitions. Have also tried memcached with identical results. |
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#5
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please post your my.cnf file
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#6
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| The MySQL databases are hosted on a separate server and no directives are specified for the MySQL client in the my.cnf for the VPS which is hosting our forums. my.cnf Directives (from DB server) Code: [mysqld] port = 3306 socket = /tmp/mysql.sock skip-locking max_allowed_packet = 4M table_cache = 64 sort_buffer_size = 512K net_buffer_length = 8K read_buffer_size = 256K read_rnd_buffer_size = 512K myisam_sort_buffer_size = 8M key_buffer = 1024M max_connections=400 log-bin=/var/log/mysql/binlog binlog-ignore-db=test,sbtest relay-log=/var/log/mysql/relay-bin relay-log-space-limit=5G server-id = 10 replicate-same-server-id = 0 auto_increment_increment = 10 auto_increment_offset = 1 log-slave-updates innodb_data_home_dir = /var/db/mysql/ innodb_data_file_path = ibdata1:10M:autoextend innodb_log_group_home_dir = /var/db/mysql/ innodb_log_arch_dir = /var/db/mysql/ innodb_buffer_pool_size = 1024M innodb_additional_mem_pool_size = 8M innodb_log_file_size = 128M innodb_log_buffer_size = 4M innodb_flush_log_at_trx_commit = 2 |
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#7
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that all looks ok. i guess the thing to suggest at this point is to upgrade apache and php
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#8
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| Solution received from vBSEO support: Changed Limit URL Length (was set to 255) to 0 - immediate drop in CPU load, application now performs exactly as expected. |
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#9
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| Quote:
Thanks |
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#11
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thanks. Mine was set to 0. Changes it to 5. As per stopword removal. Smart would be the better* setting for this instead of yes as far as server performance is concerned correct? No being the best performance setting? |
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#12
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0 (or off) is the best performance setting. any figure you put in there will require processing cycles to figure out the length and to trim it appropriately.
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| Tags |
| 100%, cpu, performance, problem, xcache |
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