Re: [PATCH 1/5] sched/fair: ignore SIS_UTIL when has idle core
From: Chen Yu
Date: Wed Aug 10 2022 - 09:50:26 EST
On Tue, Jul 12, 2022 at 4:45 PM Abel Wu <wuyun.abel@xxxxxxxxxxxxx> wrote:
>
> When SIS_UTIL is enabled, SIS domain scan will be skipped if
> the LLC is overloaded. Since the overloaded status is checked
> in the load balancing at LLC level, the interval is llc_size
> miliseconds. The duration might be long enough to affect the
> overall system throughput if idle cores are out of reach in
> SIS domain scan.
>
> Signed-off-by: Abel Wu <wuyun.abel@xxxxxxxxxxxxx>
> ---
>
Tested schbench and netperf on latest 5.19 vanilla, it seems that there
is latency performance improvement when the load is low in schbench,
and no performance difference on netperf.
./report.py -b 5.19.0+ -c 5.19.0-skip-sis-util+ -t schbench
schbench
========
case load baseline(std%) compare%( std%)
normal mthread-1 1.00 ( 0.00) +7.69 ( 0.00)
normal mthread-2 1.00 ( 0.00) +13.24 ( 0.00)
normal mthread-4 1.00 ( 0.00) -5.88 ( 0.00)
normal mthread-8 1.00 ( 0.00) -0.25 ( 0.00)
./report.py -b 5.19.0+ -c 5.19.0-skip-sis-util+ -t netperf
netperf
=======
case load baseline(std%) compare%( std%)
TCP_RR thread-28 1.00 ( 0.62) +0.15 ( 0.55)
TCP_RR thread-56 1.00 ( 0.42) -0.26 ( 0.40)
TCP_RR thread-84 1.00 ( 0.29) +0.39 ( 0.29)
TCP_RR thread-112 1.00 ( 0.22) +0.44 ( 0.23)
TCP_RR thread-140 1.00 ( 0.17) +0.33 ( 0.18)
TCP_RR thread-168 1.00 ( 0.17) +0.19 ( 0.16)
TCP_RR thread-196 1.00 ( 13.65) -0.62 ( 14.83)
TCP_RR thread-224 1.00 ( 9.80) -0.65 ( 9.67)
UDP_RR thread-28 1.00 ( 0.89) +0.92 ( 0.81)
UDP_RR thread-56 1.00 ( 0.78) +0.38 ( 0.73)
UDP_RR thread-84 1.00 ( 14.03) +0.78 ( 16.85)
UDP_RR thread-112 1.00 ( 12.26) -0.42 ( 11.95)
UDP_RR thread-140 1.00 ( 9.86) -0.89 ( 6.93)
UDP_RR thread-168 1.00 ( 11.62) -0.82 ( 8.80)
UDP_RR thread-196 1.00 ( 19.47) +0.42 ( 16.50)
UDP_RR thread-224 1.00 ( 18.68) +0.72 ( 18.50)
Tested-by: Chen Yu <yu.c.chen@xxxxxxxxx>
--
Thanks,
Chenyu