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authorRaghavendra Talur <rtalur@redhat.com>2017-07-18 11:36:19 +0530
committerJeff Darcy <jeff@pl.atyp.us>2017-07-19 14:16:19 +0000
commit33db9aff1deaa028f30516e49fdb1e8d6e31bb73 (patch)
tree36d88c93e1e83e4253b154199b0b12531d0edb39 /doc/developer-guide
parent5ccf0922208c368873120e235be0fd2975a589c1 (diff)
libglusterfs: Name threads on creation
Set names to threads on creation for easier debugging. Output of top -H -p <PID-OF-GLUSTERFSD> Before: 19773 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19774 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19775 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19776 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19777 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19778 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19779 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19780 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19781 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19782 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19783 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19784 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19785 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.01 glusterfsd 19786 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.01 glusterfsd 19787 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.01 glusterfsd 19789 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19790 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 25178 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 5398 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 7881 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd After: 19773 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19774 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glustertimer 19775 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterfsd 19776 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glustermemsweep 19777 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glustersproc0 19778 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glustersproc1 19779 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterepoll0 19780 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusteridxwrker 19781 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusteriotwr0 19782 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterbrssign 19783 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterbrswrker 19784 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterclogecon 19785 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.01 glusterclogd0 19786 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.01 glusterclogd1 19787 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.01 glusterclogd2 19789 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterposixjan 19790 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterposixfsy 25178 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterepoll1 5398 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterepoll2 7881 root 20 0 1301.3m 12.6m 8.4m S 0.0 0.1 0:00.00 glusterposixhc Change-Id: Id5f333755c1ba168a2ffaa4fce6e71c375e10703 BUG: 1254002 Updates: #271 Signed-off-by: Raghavendra Talur <rtalur@redhat.com> Reviewed-on: https://review.gluster.org/11926 Reviewed-by: Prashanth Pai <ppai@redhat.com> Smoke: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Niels de Vos <ndevos@redhat.com> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
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+Thread Naming
+================
+Gluster processes spawn many threads; some threads are created by libglusterfs
+library, while others are created by xlators. When gfapi library is used in an
+application, some threads belong to the application and some are spawned by
+gluster libraries. We also have features where n number of threads are spawned
+to act as worker threads for same operation.
+
+In all the above cases, it is useful to be able to determine the list of threads
+that exist in runtime. Naming threads when you create them is the easiest way to
+provide that information to kernel so that it can then be queried by any means.
+
+How to name threads
+-------------------
+We have two wrapper functions in libglusterfs for creating threads. They take
+name as an argument and set thread name after its creation.
+
+```C
+gf_thread_create (pthread_t *thread, const pthread_attr_t *attr,
+ void *(*start_routine)(void *), void *arg, const char *name)
+```
+
+```C
+gf_thread_create_detached (pthread_t *thread,
+ void *(*start_routine)(void *), void *arg,
+ const char *name)
+```
+
+As max name length for a thread in POSIX is only 16 characters including the
+'\0' character, you have to be a little creative with naming. Also, it is
+important that all Gluster threads have common prefix. Considering these
+conditions, we have "gluster" as prefix for all the threads created by these
+wrapper functions. It is responsibility of the owner of thread to provide the
+suffix part of the name. It does not have to be a descriptive name, as it has
+only 8 letters to work with. However, it should be unique enough such that it
+can be matched with a table which describes it.
+
+If n number of threads are spwaned to perform same function, it is must that the
+threads are numbered.
+
+Table of thread names
+---------------------
+Thread names don't have to be a descriptive; however, it should be unique enough
+such that it can be matched with a table below without ambiguity.
+
+- bdaio - block device aio
+- brfsscan - bit rot fs scanner
+- brhevent - bit rot event handler
+- brmon - bit rot monitor
+- brosign - bit rot one shot signer
+- brpobj - bit rot object processor
+- brsproc - bit rot scrubber
+- brssign - bit rot stub signer
+- brswrker - bit rot worker
+- clogc - changelog consumer
+- clogcbki - changelog callback invoker
+- clogd - changelog dispatcher
+- clogecon - changelog reverse connection
+- clogfsyn - changelog fsync
+- cloghcon - changelog history consumer
+- clogjan - changelog janitor
+- clogpoll - changelog poller
+- clogproc - changelog process
+- clogro - changelog rollover
+- ctrcomp - change time recorder compaction
+- dhtdf - dht defrag task
+- dhtdg - dht defrag start
+- dhtfcnt - dht rebalance file counter
+- ecshd - ec heal daemon
+- epollN - epoll thread
+- fdlwrker - fdl worker
+- fusenoti - fuse notify
+- fuseproc - fuse main thread
+- gdhooks - glusterd hooks
+- glfspoll - gfapi poller thread
+- idxwrker - index worker
+- iosdump - io stats dump
+- iotwr - io thread worker
+- jbrflush - jbr flush
+- leasercl - lease recall
+- memsweep - sweeper thread for mem pools
+- nfsauth - nfs auth
+- nfsnsm - nfs nsm
+- nfsudp - nfs udp mount
+- nlmmon - nfs nlm/nsm mon
+- posixaio - posix aio
+- posixfsy - posix fsync
+- posixhc - posix heal
+- posixjan - posix janitor
+- quiesce - quiesce dequeue
+- rdmaAsyn - rdma async event handler
+- rdmaehan - rdma completion handler
+- rdmarcom - rdma receive completion handler
+- rdmascom - rdma send completion handler
+- rpcsvcrh - rpcsvc request handler
+- scleanup - socket cleanup
+- shdheal - self heal daemon
+- sigwait - glusterfsd sigwaiter
+- spoller - socket poller
+- sprocN - syncop worker thread
+- tbfclock - token bucket filter token generator thread
+- tierfixl - tier fix layout
+- timer - timer thread
+- upreaper - upcall reaper