AppCDS, DynamicCDS, Leyden and JRuby

[Charles Oliver Nutter]

On Thu, Feb 13, 2025 at 8:54 AM Vladimir Ivanov <
vladimir.x.ivanov at oracle.com> wrote:

> Hi Charlie,
>
> > I'm hoping AOTCache can help us eliminate the need for --dev. Tier 2
> code is still much slower than tier 1 code.
>
> Did you mean Tier 3 vs Tier 1? Our observations are Tier2 overhead is
> quite modest (~10%).
>
> In case you observe severe performance degradation between Tier 1 and
> Tier2, please, share a benchmark to try.
>

You're right, it's not much, but it's not zero... and limiting to tier 2
wouldn't accomplish anything for us, since any profile data it collects
would never be used.

Here's default (tiered up to 4) versus limiting to tier 3, 2, and 1 for
JRuby baseline startup (hello worldish):

jruby -e 1  2.35s user 0.16s system 165% cpu 1.518 total
jruby -e 1  2.73s user 0.21s system 183% cpu 1.603 total
jruby -e 1  2.37s user 0.14s system 180% cpu 1.385 total
jruby -J-XX:TieredStopAtLevel=3 -e 1  1.74s user 0.16s system 113% cpu
1.683 total
jruby -J-XX:TieredStopAtLevel=3 -e 1  1.84s user 0.14s system 135% cpu
1.464 total
jruby -J-XX:TieredStopAtLevel=3 -e 1  1.81s user 0.15s system 136% cpu
1.442 total
jruby -J-XX:TieredStopAtLevel=2 -e 1  1.38s user 0.13s system 116% cpu
1.301 total
jruby -J-XX:TieredStopAtLevel=2 -e 1  1.42s user 0.13s system 119% cpu
1.293 total
jruby -J-XX:TieredStopAtLevel=2 -e 1  1.55s user 0.16s system 114% cpu
1.490 total
jruby -J-XX:TieredStopAtLevel=1 -e 1  1.31s user 0.11s system 118% cpu
1.195 total
jruby -J-XX:TieredStopAtLevel=1 -e 1  1.39s user 0.12s system 121% cpu
1.239 total
jruby -J-XX:TieredStopAtLevel=1 -e 1  1.36s user 0.15s system 127% cpu
1.180 total

And for "gem list" to print out all installed Ruby libraries:

jruby -S gem list > /dev/null  5.28s user 0.28s system 214% cpu 2.591 total
jruby -S gem list > /dev/null  4.92s user 0.23s system 216% cpu 2.383 total
jruby -J-XX:TieredStopAtLevel=3 -S gem list > /dev/null  3.43s user 0.19s
system 135% cpu 2.664 total
jruby -J-XX:TieredStopAtLevel=3 -S gem list > /dev/null  3.33s user 0.17s
system 145% cpu 2.402 total
jruby -J-XX:TieredStopAtLevel=3 -S gem list > /dev/null  3.58s user 0.19s
system 153% cpu 2.453 total
jruby -J-XX:TieredStopAtLevel=2 -S gem list > /dev/null  2.76s user 0.21s
system 148% cpu 1.992 total
jruby -J-XX:TieredStopAtLevel=2 -S gem list > /dev/null  2.80s user 0.20s
system 153% cpu 1.955 total
jruby -J-XX:TieredStopAtLevel=2 -S gem list > /dev/null  2.71s user 0.18s
system 144% cpu 1.994 total
jruby -J-XX:TieredStopAtLevel=1 -S gem list > /dev/null  2.50s user 0.18s
system 139% cpu 1.913 total
jruby -J-XX:TieredStopAtLevel=1 -S gem list > /dev/null  2.58s user 0.21s
system 144% cpu 1.930 total
jruby -J-XX:TieredStopAtLevel=1 -S gem list > /dev/null  2.50s user 0.16s
system 140% cpu 1.894 total
jruby -J-XX:TieredStopAtLevel=1 -S gem list > /dev/null  2.54s user 0.19s
system 144% cpu 1.888 total
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