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@@ -10201,6 +10201,18 @@ It is obviously not possible to understand what they actually do from their comm
 * `drm: Add component-aware simple encoder` allows you to see images through VNC: <<gem5-graphic-mode>>
 * `gem5: Add support for gem5's extended GIC mode` adds support for more than 8 cores: <<gem5-arm-more-than-8-cores>>
 
+==== gem5 arm Linux kernel patches boot speedup
+
+We have observed that with the kernel patches, boot is 2x faster, falling from 1m40s to 50s.
+
+With link:https://stackoverflow.com/questions/49797246/how-to-monitor-for-how-much-time-each-line-of-stdout-was-the-last-output-line-in/49797547#49797547[`ts`], we see that a large part of the difference is at the message:
+
+....
+clocksource: Switched to clocksource arch_sys_counter
+....
+
+which takes 4s on the patched kernel, and 30s on the unpatched one! TODO understand why, especially if it is a config difference, or if it actually comes from a patch.
+
 === m5out directory
 
 When you run gem5, it generates an `m5out` directory at: