GSOC 2023 ideas

marcoapc · March 20, 2023, 11:38pm

https://gitweb.dragonflybsd.org/dragonfly.git/tree/HEAD:/sys/dev/virtual/nvmm

https://gitweb.dragonflybsd.org/dragonfly.git/tree/HEAD:/sys/dev/virtual

DragonFlyBSD/DPorts/blob/master/emulators/qemu/dragonfly/patch-target_i386_nvmm_nvmm-all.c

Performance PATCH from dillon
----------------------------------------
<dillon> nvmm performance under qemu was terrible because qemu uses a global
         lock across those functions
<dillon> I adjusted the code to reduce the circumstances where the lock was
         being obtained
<dillon> it massively improved performance if I recall, when running qemu with
         a lot of cores

--- target/i386/nvmm/nvmm-all.c.orig	2022-12-14 16:28:45 UTC
+++ target/i386/nvmm/nvmm-all.c
@@ -405,12 +405,15 @@ nvmm_vcpu_pre_run(CPUState *cpu)
     uint8_t tpr;
     int ret;
 
-    qemu_mutex_lock_iothread();
-
     tpr = cpu_get_apic_tpr(x86_cpu->apic_state);
     if (tpr != qcpu->tpr) {
-        qcpu->tpr = tpr;

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