Re: [Gluster-devel] [Gluster-users] GlusterFS (3.3.1) - performance issues - large number of LOOKUP calls & high CPU usage

[Stephan von Krawczynski]

What kind of kernel are you using? Your googled article turns round kernel
versions 2.6.something.
I really do wonder if the same effects show up on recent 3.9.(7) ...


On Fri, 21 Jun 2013 11:53:41 +0800
"Song" <address@hidden> wrote:

> I use perf top and try to see where in the kernel code all this time was
> being spend. Following is what I was seeing:
> 
>  
> 
> PerfTop: 2036 irqs/sec kernel:100.0% exact: 0.0% [1000Hz cycles],
> (target_pid: 5336)
> 
> ----------------------------------------------------------------------------
> ------------------------------
> 
>  
> 
> samples pcnt function DSO
> 
> _______ _____ _________________________ _________________
> 
>  
> 
> 11265.00 91.0% _spin_lock_irq [kernel.kallsyms]
> 
> 355.00 2.9% _spin_lock_irqsave [kernel.kallsyms]
> 
> 249.00 2.0% compaction_alloc [kernel.kallsyms]
> 
> 235.00 1.9% compact_zone [kernel.kallsyms]
> 
> 151.00 1.2% get_pageblock_flags_group [kernel.kallsyms]
> 
> 32.00 0.3% _cond_resched [kernel.kallsyms]
> 
> 27.00 0.2% copy_page_c [kernel.kallsyms]
> 
> 8.00 0.1% _spin_lock [kernel.kallsyms]
> 
> 6.00 0.0% mem_cgroup_del_lru_list [kernel.kallsyms]
> 
> 5.00 0.0% __wake_up_bit [kernel.kallsyms]
> 
>  
> 
> Then, I use “perf record  -g -p 5336” to capture the percent of kernel
> call and find “compact_zone” is very busy.
> 
>  
> 
> address@hidden ~]# perf report --stdio
> 
> # Events: 47K cycles
> 
> #
> 
> # Overhead    Command          Shared Object
> Symbol
> 
> # ........  .........  .....................
> ......................................
> 
> #
> 
>     91.51%  glusterfs  [kernel.kallsyms]      [k] _spin_lock_irq
> 
>             |
> 
>             --- _spin_lock_irq
> 
>                |          
> 
>                |--99.64%-- compact_zone
> 
>                |          compact_zone_order
> 
>                |          try_to_compact_pages
> 
>                |          __alloc_pages_nodemask
> 
>                |          alloc_pages_vma
> 
>                |          do_huge_pmd_anonymous_page
> 
>                |          handle_mm_fault
> 
>                |          __do_page_fault
> 
>                |          do_page_fault
> 
>                |          page_fault
> 
>                |          |          
> 
>                |          |--94.45%-- xdr_callmsg_internal
> 
>                |          |          0x3829b98860
> 
>                |          |          
> 
>                |           --5.55%-- __memcpy_sse2
> 
>                 --0.36%-- [...]
> 
>  
> 
> Last, I google “compact_zone” and find the article “Linux 6 Transparent
> Huge Pages and Hadoop Workloads
> <http://structureddata.org/2012/06/18/linux-6-transparent-huge-pages-and-had
> oop-workloads/> ”. The sample issues is occurred in hadoop.
> 
> THP can be disabled by running the following command:
> 
> echo never > /sys/kernel/mm/redhat_transparent_hugepage/enabled
> 
>  
> 
> CPU usage and work load is normal.
> 
>  
> 
> From: address@hidden
> [mailto:address@hidden On Behalf Of Song
> Sent: Friday, June 07, 2013 1:34 PM
> To: 'Stephan von Krawczynski'; 'Pablo'
> Cc: address@hidden
> Subject: Re: [Gluster-devel] [Gluster-users] GlusterFS (3.3.1) - performance
> issues - large number of LOOKUP calls & high CPU usage
> 
>  
> 
> We have met same performance issues when open a file. Sometime, it cost more
> than 10 seconds that a file open.
> 
>  
> 
> We add some debug info to locate this problem and test again and again, find
> it's will cost a few seconds when execute 'xdr_callmsg' function in
> 'rpc_request_to_xdr'.
> 
>  
> 
> A typical example of log is as below. From [2013-06-06 13:34:59.471004] to
> [2013-06-06 13:35:04.890363] , 'xdr_callmsg' function cost more than 5
> seconds.
> 
>  
> 
> [2013-06-06 13:34:59.470991] I
> [rpc-clnt.c:1175:rpc_clnt_record_build_record] 0-gfs1-client-51: (thread_id
> is 140257410492160 )add for open_slow rpc_fill_request_end
> 
> [2013-06-06 13:34:59.471004] I [xdr-rpcclnt.c:87:rpc_request_to_xdr] 0-rpc:
> (thread_id is 140257410492160 len = 131072 )add for open_slow
> xdrmem_create_end
> 
> [2013-06-06 13:34:59.570044] I [client.c:124:client_submit_request]
> 0-gfs1-client-86: (thread_id is 140257819739904 )add for open_slow
> rpc_clnt_submit
> 
> [2013-06-06 13:34:59.570091] I [rpc-clnt.c:1363:rpc_clnt_submit]
> 0-gfs1-client-86: (thread_id is 140257819739904 )add for open_slow callid
> end
> 
>  
> 
> ......
> 
>  
> 
> [2013-06-06 13:34:59.579865] I [client3_1-fops.c:2235:client3_1_lookup_cbk]
> 0-gfs1-client-5: (thread_id is 140257819739904)add for open_slow lookup_cbk
> path=/xmail_dedup/gfs1_000/1FA/1B1
> 
> [2013-06-06 13:34:59.579917] I [client3_1-fops.c:2235:client3_1_lookup_cbk]
> 0-gfs1-client-6: (thread_id is 140257819739904)add for open_slow lookup_cbk
> path=/xmail_dedup/gfs1_000/1FA/1B1
> 
> [2013-06-06 13:35:04.890363] I [xdr-rpcclnt.c:92:rpc_request_to_xdr] 0-rpc:
> (thread_id is 140257410492160 )add for open_slow xdr_callmsg_end
> 
> [2013-06-06 13:35:04.890366] I [client.c:110:client_submit_request]
> 0-gfs1-client-44: (thread_id is 140257785079552 )add for open_slow create
> the xdr payload
> 
>  
> 
>  
> 
> Native client and use 5 glusterfs in one server. When performance issues
> appear, the cpu usage is as below:
> 
>  
> 
> top - 13:45:37 up 57 days, 14:04,  4 users,  load average: 6.98, 5.38, 4.67
> 
> Tasks: 712 total,   8 running, 704 sleeping,   0 stopped,   0 zombie
> 
> Cpu(s):  3.2%us, 63.5%sy,  0.0%ni, 31.5%id,  1.4%wa,  0.0%hi,  0.4%si,
> 0.0%st
> 
> Mem:  65956748k total, 55218008k used, 10738740k free,  3362972k buffers
> 
> Swap:  8388600k total,    41448k used,  8347152k free, 37370840k cached
> 
>  
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 
> 13905 root      20   0  554m 363m 2172 R 244.8  0.6   9:51.01 glusterfs
> 
> 13650 root      20   0  766m 610m 2056 R 184.8  0.9  18:24.37 glusterfs
> 
> 13898 root      20   0  545m 356m 2176 R 179.2  0.6  12:04.87 glusterfs
> 
> 13919 root      20   0  547m 360m 2172 R 111.6  0.6   9:16.89 glusterfs
> 
> 22460 root      20   0  486m 296m 2200 S 100.4  0.5 194:59.10 glusterfs 
> 
> 13878 root      20   0  545m 361m 2176 R 99.7  0.6   8:35.88 glusterfs 
> 
>  
> 
>  
> 
> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On Behalf Of Stephan von
> Krawczynski
> Sent: Thursday, June 06, 2013 10:07 PM
> To: Pablo
> Cc: address@hidden
> Subject: Re: [Gluster-users] GlusterFS (3.3.1) - performance issues - large
> number of LOOKUP calls & high CPU usage
> 
>  
> 
> On Thu, 06 Jun 2013 10:39:21 -0300
> 
> Pablo < <mailto:address@hidden> address@hidden> wrote:
> 
>  
> 
> > I have never try this (In fact I'm just learning a bit more how to 
> 
> > administer a Gluster server.), buy you may find it useful.
> 
> > 
> 
> >
> <http://download.gluster.org/pub/gluster/glusterfs/doc/HA%20and%20Load%25>
> http://download.gluster.org/pub/gluster/glusterfs/doc/HA%20and%20Load%
> 
> > 20Balancing%20for%20NFS%20and%20SMB.html
> 
> > 
> 
> > Pablo.
> 
>  
> 
> The thing with this way of failover is though, that you will likely corrupt
> a currently written file. If your NFS-server (gluster) node dies while you
> write your file will be corrupt. If you use native glusterfs mounts it will
> not (should not). This is why I consider the NFS server feature nothing more
> than a bad hack. It does not deliver the safety that glusterfs promises,
> even if you solve the failover problem somehow.
> 
>  
> 
> --
> 
> Regards,
> 
> Stephan
> 
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