On Mon 2018-07-23 12:00:08, Linus Torvalds wrote: > On Mon, Jul 23, 2018 at 7:09 AM Pavel Machek <pavel@xxxxxx> wrote: > > > > Meanwhile... it looks like gcc is not slowed down significantly, but > > other stuff sees 30% .. 40% slowdowns... which is rather > > significant. > > That is more or less expected. Ok, so I was wrong. bzip2 showed 30% slowdown, but running test in a loop, I get (on v4.18) that, too. That tells me that something is wrong with machine I'm using for benchmarking. Whether KPTI is enabled can still be measured with the bzip2 pipeline, but the effect is far more subtle. Pavel pavel@amd:~$ while true; do time cat /dev/urandom | head -c 10000000 | bzip2 -9 - | wc -c ; done10044031 3.87user 0.91system 4.62 (0m4.622s) elapsed 103.48%CPU 10044234 4.03user 0.82system 4.68 (0m4.688s) elapsed 103.67%CPU 10043664 4.28user 0.85system 4.99 (0m4.994s) elapsed 102.90%CPU 10045959 4.43user 0.85system 5.12 (0m5.121s) elapsed 103.44%CPU 10043829 4.50user 0.89system 5.22 (0m5.228s) elapsed 103.22%CPU 10044296 4.65user 0.93system 5.39 (0m5.398s) elapsed 103.61%CPU 10045311 4.76user 0.93system 5.47 (0m5.479s) elapsed 103.98%CPU 10043819 4.81user 0.93system 5.55 (0m5.556s) elapsed 103.37%CPU 10045097 4.72user 1.04system 5.59 (0m5.597s) elapsed 103.01%CPU 10044012 4.86user 0.97system 5.68 (0m5.684s) elapsed 102.79%CPU 10044569 4.93user 0.96system 5.72 (0m5.728s) elapsed 102.92%CPU 10044141 4.94user 0.98system 5.75 (0m5.752s) elapsed 102.97%CPU 10043695 4.97user 0.95system 5.76 (0m5.768s) elapsed 102.87%CPU 10045690 5.12user 0.94system 5.90 (0m5.901s) elapsed 102.79%CPU 10045153 5.06user 1.00system 5.88 (0m5.883s) elapsed 103.21%CPU 10044560 5.10user 1.01system 5.92 (0m5.927s) elapsed 103.31%CPU 10044845 5.17user 0.99system 5.96 (0m5.960s) elapsed 103.44%CPU 10043884 5.15user 1.03system 6.00 (0m6.004s) elapsed 103.14%CPU 10044286 5.18user 1.01system 6.00 (0m6.002s) elapsed 103.40%CPU 10045749 5.00user 1.22system 6.04 (0m6.044s) elapsed 102.98%CPU 10044098 5.22user 1.02system 6.05 (0m6.053s) elapsed 103.21%CPU 10045326 5.20user 1.01system 6.04 (0m6.048s) elapsed 102.72%CPU 10042365 5.22user 1.03system 6.06 (0m6.061s) elapsed 103.30%CPU 10043952 5.24user 1.00system 6.06 (0m6.069s) elapsed 102.97%CPU 10044569 5.30user 1.00system 6.09 (0m6.099s) elapsed 103.46%CPU 10043241 5.26user 1.00system 6.09 (0m6.097s) elapsed 102.79%CPU 10044797 5.30user 1.01system 6.11 (0m6.114s) elapsed 103.46%CPU 10043711 5.25user 1.02system 6.09 (0m6.093s) elapsed 103.03%CPU 10043882 5.31user 1.01system 6.13 (0m6.131s) elapsed 103.28%CPU 10043571 5.26user 1.05system 6.13 (0m6.133s) elapsed 103.06%CPU 10044742 5.29user 1.03system 6.12 (0m6.122s) elapsed 103.25%CPU 10044170 5.35user 1.04system 6.18 (0m6.183s) elapsed 103.60%CPU 10043542 5.22user 1.12system 6.17 (0m6.172s) elapsed 102.89%CPU 10042985 5.25user 1.13system 6.19 (0m6.193s) elapsed 103.09%CPU 10044102 5.36user 1.01system 6.17 (0m6.177s) elapsed 103.17%CPU 10044609 5.48user 0.99system 6.28 (0m6.284s) elapsed 103.11%CPU 10045185 5.40user 1.03system 6.23 (0m6.236s) elapsed 103.29%CPU 10044444 5.41user 1.06system 6.25 (0m6.255s) elapsed 103.55%CPU 10044859 5.35user 1.04system 6.20 (0m6.201s) elapsed 103.17%CPU 10045613 -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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