diff options
Diffstat (limited to 'share/man/man7')
| -rw-r--r-- | share/man/man7/tuning.7 | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/share/man/man7/tuning.7 b/share/man/man7/tuning.7 index f95047b..0f962ca 100644 --- a/share/man/man7/tuning.7 +++ b/share/man/man7/tuning.7 @@ -403,13 +403,16 @@ on the system. .Pp The .Va kern.ipc.maxpipekva -loader tunable is used to set a hard limit on the amount of pageable -address space available. -This value is auto tuned by the system, but may require manual tuning -in a few rare cases. +loader tunable is used to set a hard limit on the +amount of kernel address space allocated to mapping of pipe buffers. +Use of the mapping allows the kernel to eliminate a copy of the +data from writer address space into the kernel, directly copying +the content of mapped buffer to the reader. Increasing this value to a higher setting, such as `25165824' might -improve performance on systems where pageable address space is -quickly exhausted. +improve performance on systems where space for mapping pipe buffers +is quickly exhausted. +This exhaustion is not fatal; however, and it will only cause pipes to +to fall back to use double-copy. .Pp The .Va kern.ipc.shm_use_phys |
