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Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index dd0bfc291a682e..fe11fccf7e41bd 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -856,6 +856,49 @@ running once the system is up. mga= [HW,DRM] + migration_cost= + [KNL,SMP] debug: override scheduler migration costs + Format: <level-1-usecs>,<level-2-usecs>,... + This debugging option can be used to override the + default scheduler migration cost matrix. The numbers + are indexed by 'CPU domain distance'. + E.g. migration_cost=1000,2000,3000 on an SMT NUMA + box will set up an intra-core migration cost of + 1 msec, an inter-core migration cost of 2 msecs, + and an inter-node migration cost of 3 msecs. + + WARNING: using the wrong values here can break + scheduler performance, so it's only for scheduler + development purposes, not production environments. + + migration_debug= + [KNL,SMP] migration cost auto-detect verbosity + Format=<0|1|2> + If a system's migration matrix reported at bootup + seems erroneous then this option can be used to + increase verbosity of the detection process. + We default to 0 (no extra messages), 1 will print + some more information, and 2 will be really + verbose (probably only useful if you also have a + serial console attached to the system). + + migration_factor= + [KNL,SMP] multiply/divide migration costs by a factor + Format=<percent> + This debug option can be used to proportionally + increase or decrease the auto-detected migration + costs for all entries of the migration matrix. + E.g. migration_factor=150 will increase migration + costs by 50%. (and thus the scheduler will be less + eager migrating cache-hot tasks) + migration_factor=80 will decrease migration costs + by 20%. (thus the scheduler will be more eager to + migrate tasks) + + WARNING: using the wrong values here can break + scheduler performance, so it's only for scheduler + development purposes, not production environments. + mousedev.tap_time= [MOUSE] Maximum time between finger touching and leaving touchpad surface for touch to be considered |