Re: [PATCH] sched/fair: Let sync wakeups target the waker's core

[Kayra Cizmeci]

Hi Vineeth,

Since all the numbers on this thread are from POWER, I ran this on x86 (Zen 3). I ran the test 3 times on both
baseline and baseline + patch. 

I first got the baseline from 0d83957076 that was like that: 

=num===cycles===cache-misses= 
[ 1: 11266587459: 19064897  ]
[ 2: 11329575367: 18860444  ]
[ 3: 11283159019: 19121436  ]

Then, I got the 0d83957076 + this patch:

=num===cycles===cache-misses=
[ 1: 11128721747: 19886131  ]
[ 2: 11163014797: 20019508  ]
[ 3: 11111832330: 19764849  ]

I tested them with AMD Ryzen 7 5700X 8 Cores, 16 Threads or by other means SMT2. Busybox, minimal initramfs and 
perf or to be more specific, this command: perf stat -r 10 -e cycles,cache-misses perf bench sched pipe

There is a 1.40% decrease of cycles baseline to this patch while there is a 4.60% increase in cache-misses. 
Both of these values are average values of the decrease and the increase. The values also don't overlap.

I don't really have explanations for why this values came back like that, 
I wasn't expecting them to be like this. Especially cache-misses.

Tested-by: Kayra Cizmeci <kayracizmeci@xxxxxxxxx>

Thanks,
Kayra