On 11/8/18 6:00 AM, Sebastian Andrzej Siewior wrote:
On 2018-11-06 15:34:55 [-0600], Grygorii Strashko wrote:
Hi All,
Hi,
Do anybody tried to use ARM64 RT with 76K pages enabled?
75 would be an off by one but this :)
Ops 8-). at least subj is correct.
My attempt shows that enabling CONFIG_ARM64_64K_PAGES=y increases latencies by ~30%
cyclictest -n -m -Sp98 -q -D2m with CONFIG_ARM64_64K_PAGES=y
T: 0 ( 772) P:98 I:1000 C: 120000 Min: 7 Act: 13 Avg: 10 Max: 85
T: 1 ( 773) P:98 I:1500 C: 79998 Min: 7 Act: 13 Avg: 10 Max: 71
T: 2 ( 774) P:98 I:2000 C: 59997 Min: 7 Act: 11 Avg: 11 Max: 64
T: 3 ( 775) P:98 I:2500 C: 47996 Min: 7 Act: 14 Avg: 12 Max: 66
cyclictest -n -m -Sp98 -q -D2m with CONFIG_ARM64_64K_PAGES=n
T: 0 ( 697) P:98 I:1000 C: 120000 Min: 7 Act: 10 Avg: 9 Max: 38
T: 1 ( 698) P:98 I:1500 C: 79987 Min: 7 Act: 10 Avg: 10 Max: 32
T: 2 ( 699) P:98 I:2000 C: 59981 Min: 7 Act: 14 Avg: 11 Max: 46
T: 3 ( 700) P:98 I:2500 C: 47977 Min: 6 Act: 11 Avg: 10 Max: 45
So this is an idle system?
Yes (in general) - it's collected with systemd, so some daemons are active.
The Kconfig help says "faster TLB lookup". Interesting.
Are the 16k pages in between (latency wise) by any chance?
I'll try it.
--
regards,
-grygorii
