On Thu, 2018-02-15 at 10:07 -0800, Rohit Jain wrote: > > > Rohit is running more tests with a patch that deletes > > sysctl_sched_migration_cost from idle_balance, and for his patch but > > with the 5000 usec mistake corrected back to 500 usec. So far both > > give improvements over the baseline, but for different cases, so we > > need to try more workloads before we draw any conclusions. > > > > Rohit, can you share your data so far? > > Results: > > In the following results, "Domain based" approach is as mentioned in the > RFC sent out with the values fixed (As pointed out by Mike). "No check" is > the patch where I just remove the check against sysctl_sched_migration_cost > > 1) Hackbench results on 2 socket, 44 core and 88 threads Intel x86 machine > (lower is better): > > +--------------+-----------------+--------------------------+-------------------------+ > | | Without Patch |Domain Based |No Check > | > +------+-------+--------+--------+-----------------+--------+----------------+--------+ > |Loops | Groups|Average |%Std Dev|Average |%Std Dev|Average > |%Std Dev| > +------+-------+--------+--------+-----------------+--------+----------------+--------+ > |100000| 4 |9.701 |0.78 |7.971 (+17.84%) | 1.34 |8.919 (+8.07%) > |1.07 | > |100000| 8 |17.186 |0.77 |16.712 (+2.76%) | 0.87 |17.043 (+0.83%) > |0.83 | > |100000| 16 |30.378 |0.55 |29.780 (+1.97%) | 0.38 |29.565 (+2.67%) > |0.29 | > |100000| 32 |54.712 |0.54 |53.001 (+3.13%) | 0.19 |52.158 (+4.67%) > |0.22 | > +------+-------+--------+--------+-----------------+--------+----------------+--------+
previous numbers. +-------+----+-------+-------------------+--------------------------+ | | | | Without patch |With patch | +-------+----+-------+---------+---------+----------------+---------+ |Loops |FD |Groups | Average |%Std Dev |Average |%Std Dev | +-------+----+-------+---------+---------+----------------+---------+ |100000 |40 |4 | 9.701 |0.78 |9.623 (+0.81%) |3.67 | |100000 |40 |8 | 17.186 |0.77 |17.068 (+0.68%) |1.89 | |100000 |40 |16 | 30.378 |0.55 |30.072 (+1.52%) |0.46 | |100000 |40 |32 | 54.712 |0.54 |53.588 (+2.28%) |0.21 | +-------+----+-------+---------+---------+----------------+---------+ My take on this (not that you have to sell it to me, you don't) when I squint at these together is submit the one-liner, and take the rest back to the drawing board. You've got nothing but high std dev numbers in (imo) way too finicky/unrealistic hackbench to sell these not so pretty patches. I bet you can easily sell that one-liner, because that removes an old wart (me stealing migration_cost in the first place), instead of making wart a whole lot harder to intentionally not notice. -Mike