Song Jiacheng has posted comments on this change. ( http://gerrit.cloudera.org:8080/20716 )
Change subject: [util] add a warning into 'heap_sample_every_n_bytes' flag description. ...................................................................... Patch Set 8: (7 comments) > Patch Set 7: > > (1 comment) http://gerrit.cloudera.org:8080/#/c/20716/7//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/20716/7//COMMIT_MSG@9 PS7, Line 9: Parameter --heap_sample_every_n_byt > nit: --heap_sample_every_n_bytes Done http://gerrit.cloudera.org:8080/#/c/20716/7//COMMIT_MSG@10 PS7, Line 10: to a positive value will > nit: a positive value Done http://gerrit.cloudera.org:8080/#/c/20716/7//COMMIT_MSG@11 PS7, Line 11: , > Remove it. Done http://gerrit.cloudera.org:8080/#/c/20716/7//COMMIT_MSG@12 PS7, Line 12: comp > nit: compete the lock of page heap with other thread? Done http://gerrit.cloudera.org:8080/#/c/20716/7//COMMIT_MSG@18 PS7, Line 18: > nit: --heap_sample_every_n_bytes Done http://gerrit.cloudera.org:8080/#/c/20716/7/src/kudu/util/flags.cc File src/kudu/util/flags.cc: http://gerrit.cloudera.org:8080/#/c/20716/7/src/kudu/util/flags.cc@100 PS7, Line 100: "in tcmalloc; the lower the value, the higher the lock contention."); > Is it necessary to remove the former description? 524288 is a recommend val I have tested 524288 in a high throughput environment, and the stacks show that the apply threads of tserver always stuck in DoSampleAllocation() or Free(). There are 48 apply threads per tserver, but only a few of them could work at the meantime. Taking one sample once every 512KB allocation is really too often in production environment. http://gerrit.cloudera.org:8080/#/c/20716/7/src/kudu/util/flags.cc@99 PS7, Line 99: Warning: Setting this flag to a positive value increases lock contention " : "in tcmalloc; the lower the value, the higher the lock contention. > It seems better to set --heap_sample_every_n_bytes more larger to lower the I think it should depend on the memory limit and throughput of the tserver, like 1% of hard limit could be accepted. -- To view, visit http://gerrit.cloudera.org:8080/20716 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I00d55126f0cad0ac6cc130576cc45808f96f0a47 Gerrit-Change-Number: 20716 Gerrit-PatchSet: 8 Gerrit-Owner: Song Jiacheng <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Reviewer: Marton Greber <[email protected]> Gerrit-Reviewer: Song Jiacheng <[email protected]> Gerrit-Reviewer: Wang Xixu <[email protected]> Gerrit-Reviewer: Yingchun Lai <[email protected]> Gerrit-Comment-Date: Mon, 18 Dec 2023 07:22:00 +0000 Gerrit-HasComments: Yes
