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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-02-13 13:26:20 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-02-13 13:26:20 +0100 |
| commit | 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 (patch) | |
| tree | 536d8a92976e675b484b35dec88d40c97fab8ac8 /drivers/kvm | |
| parent | 54413927f022292aeccadd268fbf1c0b42129945 (diff) | |
| download | linux-3.10-464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28.tar.gz linux-3.10-464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28.tar.bz2 linux-3.10-464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28.zip | |
[PATCH] i386: Convert i386 PDA code to use %fs
Convert the PDA code to use %fs rather than %gs as the segment for
per-processor data. This is because some processors show a small but
measurable performance gain for reloading a NULL segment selector (as %fs
generally is in user-space) versus a non-NULL one (as %gs generally is).
On modern processors the difference is very small, perhaps undetectable.
Some old AMD "K6 3D+" processors are noticably slower when %fs is used
rather than %gs; I have no idea why this might be, but I think they're
sufficiently rare that it doesn't matter much.
This patch also fixes the math emulator, which had not been adjusted to
match the changed struct pt_regs.
[frederik.deweerdt@gmail.com: fixit with gdb]
[mingo@elte.hu: Fix KVM too]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Ian Campbell <Ian.Campbell@XenSource.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Zachary Amsden <zach@vmware.com>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'drivers/kvm')
| -rw-r--r-- | drivers/kvm/vmx.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 1e640b89917..fd4e9173438 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -1879,12 +1879,6 @@ again: asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS)); - /* - * Profile KVM exit RIPs: - */ - if (unlikely(prof_on == KVM_PROFILING)) - profile_hit(KVM_PROFILING, (void *)vmcs_readl(GUEST_RIP)); - kvm_run->exit_type = 0; if (fail) { kvm_run->exit_type = KVM_EXIT_TYPE_FAIL_ENTRY; @@ -1907,6 +1901,12 @@ again: reload_tss(); } + /* + * Profile KVM exit RIPs: + */ + if (unlikely(prof_on == KVM_PROFILING)) + profile_hit(KVM_PROFILING, (void *)vmcs_readl(GUEST_RIP)); + vcpu->launched = 1; kvm_run->exit_type = KVM_EXIT_TYPE_VM_EXIT; r = kvm_handle_exit(kvm_run, vcpu); |