Re: [PATCH 0/3] PTI for x86-32 Fixes and Updates

From: Pavel Machek
Date: Mon Jul 23 2018 - 10:09:31 EST


Hi!

> here are 3 patches which update the PTI-x86-32 patches recently merged
> into the tip-tree. The patches are ordered by importance:

It seems PTI is now in -next. I'll test that soon.

Meanwhile... it looks like gcc is not slowed down significantly, but
other stuff sees 30% .. 40% slowdowns... which is rather
significant.

Would it be possible to have per-process control of kpti? I have
some processes where trading of speed for security would make sense.

Best regards,
Pavel

cd ~/g/tui/nowcast
time ./nowcast -x (30%)
KPTI: 139.25user 73.65system 269.90 (4m29.901s) elapsed 78.88%CPU
133.35user 73.15system 228.80 (3m48.802s) elapsed 90.25%CPU
140.51user 74.21system 218.33 (3m38.338s) elapsed 98.34%CPU
133.85user 75.89system 212.02 (3m32.026s) elapsed 98.93%CPU (no chromium)
139.34user 75.00system 235.75 (3m55.752s) elapsed 90.92%CPU

4.18: 116.99user 43.79system 217.65 (3m37.653s) elapsed 73.87%CPU
115.14user 43.97system 178.85 (2m58.855s) elapsed 88.96%CPU
128.47user 47.22system 178.24 (2m58.245s) elapsed 98.57%CPU
132.30user 49.27system 184.40 (3m4.408s) elapsed 98.46%CPU
134.88user 48.59system 186.67 (3m6.673s) elapsed 98.29%CPU
132.15user 48.65system 524.68 (8m44.684s) elapsed 34.46%CPU
120.38user 45.45system 168.72 (2m48.720s) elapsed 98.29%CPU

time cat /dev/urandom | head -c 10000000 | bzip2 -9 - | wc -c (40%)
v4.18: 4.57user 0.23system 4.64 (0m4.644s) elapsed 103.53%CPU
4.86user 0.23system 4.95 (0m4.952s) elapsed 102.81%CPU
5.13user 0.22system 5.19 (0m5.190s) elapsed 103.14%CPU
KPTI: 6.39user 0.48system 6.74 (0m6.747s) elapsed 101.96%CPU
6.66user 0.41system 6.91 (0m6.912s) elapsed 102.51%CPU
6.53user 0.51system 6.91 (0m6.919s) elapsed 101.99%CPU

v4l-utils: make clean, time make
v4.18: 191.93user 11.00system 211.19 (3m31.191s) elapsed 96.09%CPU
221.21user 14.69system 248.73 (4m8.734s) elapsed 94.84%CPU
198.35user 11.61system 211.39 (3m31.392s) elapsed 99.32%CPU
204.87user 11.69system 217.97 (3m37.971s) elapsed 99.35%CPU
203.68user 11.88system 217.29 (3m37.291s) elapsed 99.20%CPU
KPTI: 156.45user 40.08system 204.77 (3m24.777s) elapsed 95.97%CPU
183.32user 38.64system 225.03 (3m45.031s) elapsed 98.63%CPU

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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