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authorChristian Krinitsin <mail@krinitsin.com>2025-07-03 07:27:52 +0000
committerChristian Krinitsin <mail@krinitsin.com>2025-07-03 07:27:52 +0000
commitd0c85e36e4de67af628d54e9ab577cc3fad7796a (patch)
treef8f784b0f04343b90516a338d6df81df3a85dfa2 /results/classifier/gemma3:12b/hypervisor/1898011
parent7f4364274750eb8cb39a3e7493132fca1c01232e (diff)
downloadqemu-analysis-d0c85e36e4de67af628d54e9ab577cc3fad7796a.tar.gz
qemu-analysis-d0c85e36e4de67af628d54e9ab577cc3fad7796a.zip
add deepseek and gemma results
Diffstat (limited to 'results/classifier/gemma3:12b/hypervisor/1898011')
-rw-r--r--results/classifier/gemma3:12b/hypervisor/189801131
1 files changed, 31 insertions, 0 deletions
diff --git a/results/classifier/gemma3:12b/hypervisor/1898011 b/results/classifier/gemma3:12b/hypervisor/1898011
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+++ b/results/classifier/gemma3:12b/hypervisor/1898011
@@ -0,0 +1,31 @@
+
+mmap MAP_NORESERVE of 2^42 bytes consumes 16Gb of actual RAM
+
+Run this program: 
+
+#include <sys/mman.h>
+#include <stdio.h>
+int main() {
+        for (int i = 30; i <= 44; i++) {
+                fprintf(stderr, "trying 2**%d\n", i);
+                mmap((void*)0x600000000000,1ULL << i,
+                        PROT_NONE,
+                        MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_NORESERVE,-1,0);
+        }
+}
+
+(tried qemu-x86_64 and qemu-aarch64, 4.2.1 and trunk/5.1.50)
+
+On each iteration qemu will consume 2x more physical RAM, 
+e.g. when mapping 2^42 it will have RSS of 16Gb.
+
+On normal linux it works w/o consuming much RAM, due to MAP_NORESERVE. 
+
+Also: qemu -strace prints 0 instead of the correct size starting from size=2^32
+and prints -2147483648 for size=2^31. 
+
+mmap(0x0000600000000000,1073741824,PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_NORESERVE,-1,0) = 0x0000600000000000
+
+mmap(0x0000600000000000,-2147483648,PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_NORESERVE,-1,0) = 0x0000600000000000
+
+mmap(0x0000600000000000,0,PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_NORESERVE,-1,0) = 0x0000600000000000
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