Well, color me very confused. In a CPU bound workload two cores on the same socket have substantially different performance (32% slowdown). If I just migrate the running process between the cores, performance changes immediately.
This is on 2x Xeon 5215 system.
I checked that it's not thermals, cpu frequency/boost and the system is idle.
Here's the odd part: The biggest difference evident in perf counters is
a 2.5x difference in icache_64b.iftag_stall, with ~same icache_64b.iftag_miss.
AndresFreundTec /
npub1ly…gks2j
2024-05-26 08:55:32
Author Public Key
npub1ly44p7gfxnqm237hpxc8dynusdz4jfvtqrh5nmgrwcrsxkmz5n6q6gks2jPublished at
2024-05-26 08:55:32Event JSON
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"content": "Well, color me very confused. In a CPU bound workload two cores on the same socket have substantially different performance (32% slowdown). If I just migrate the running process between the cores, performance changes immediately.\n\nThis is on 2x Xeon 5215 system.\n\nI checked that it's not thermals, cpu frequency/boost and the system is idle.\n\nHere's the odd part: The biggest difference evident in perf counters is\na 2.5x difference in icache_64b.iftag_stall, with ~same icache_64b.iftag_miss.",
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