similar to: [PATCH RFC v3 6/6] KVM guest: introduce smart idle poll algorithm

From: Quan Xu <quan.xu0 at gmail.com> the last idle loop is from tick_nohz_idle_enter to tick_nohz_idle_exit. Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> Signed-off-by: Quan Xu <quan.xu0 at gmail.com> Cc: Frederic Weisbecker <fweisbec at gmail.com> Cc: Thomas Gleixner <tglx at linutronix.de> Cc: Ingo Molnar <mingo at kernel.org> Cc: linux-kernel at

From: Quan Xu <quan.xu0 at gmail.com> the last idle loop is from tick_nohz_idle_enter to tick_nohz_idle_exit. Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> Signed-off-by: Quan Xu <quan.xu0 at gmail.com> Cc: Frederic Weisbecker <fweisbec at gmail.com> Cc: Thomas Gleixner <tglx at linutronix.de> Cc: Ingo Molnar <mingo at kernel.org> Cc: linux-kernel at

From: Quan Xu <quan.xu0 at gmail.com> To reduce the cost of poll, we introduce three sysctl to control the poll time when running as a virtual machine with paravirt. Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> Signed-off-by: Quan Xu <quan.xu0 at gmail.com> --- Documentation/sysctl/kernel.txt | 35 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/paravirt.c

From: Quan Xu <quan.xu0 at gmail.com> To reduce the cost of poll, we introduce three sysctl to control the poll time when running as a virtual machine with paravirt. Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> Signed-off-by: Quan Xu <quan.xu0 at gmail.com> --- Documentation/sysctl/kernel.txt | 35 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/paravirt.c

On 2017/11/13 23:08, Ingo Molnar wrote: > * Quan Xu <quan.xu04 at gmail.com> wrote: > >> From: Quan Xu <quan.xu0 at gmail.com> >> >> To reduce the cost of poll, we introduce three sysctl to control the >> poll time when running as a virtual machine with paravirt. >> >> Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> >>

On 2017/11/13 23:08, Ingo Molnar wrote: > * Quan Xu <quan.xu04 at gmail.com> wrote: > >> From: Quan Xu <quan.xu0 at gmail.com> >> >> To reduce the cost of poll, we introduce three sysctl to control the >> poll time when running as a virtual machine with paravirt. >> >> Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> >>

* Quan Xu <quan.xu0 at gmail.com> wrote: > > > On 2017/11/13 23:08, Ingo Molnar wrote: > > * Quan Xu <quan.xu04 at gmail.com> wrote: > > > > > From: Quan Xu <quan.xu0 at gmail.com> > > > > > > To reduce the cost of poll, we introduce three sysctl to control the > > > poll time when running as a virtual machine with

From: Yang Zhang <yang.zhang.wz at gmail.com> Some latency-intensive workload have seen obviously performance drop when running inside VM. The main reason is that the overhead is amplified when running inside VM. The most cost I have seen is inside idle path. This patch introduces a new mechanism to poll for a while before entering idle state. If schedule is needed during poll, then we

From: Yang Zhang <yang.zhang.wz at gmail.com> Some latency-intensive workload have seen obviously performance drop when running inside VM. The main reason is that the overhead is amplified when running inside VM. The most cost I have seen is inside idle path. This patch introduces a new mechanism to poll for a while before entering idle state. If schedule is needed during poll, then we

* Quan Xu <quan.xu04 at gmail.com> wrote: > From: Quan Xu <quan.xu0 at gmail.com> > > To reduce the cost of poll, we introduce three sysctl to control the > poll time when running as a virtual machine with paravirt. > > Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> > Signed-off-by: Quan Xu <quan.xu0 at gmail.com> > --- >

Hi there, I''ve been using OpenSolaris for three months now, and I''ve started to get interested about to get my hands dirty with DTrace. Since I have an strong GNOME background, I would like to use it to help GNOME developers to find performance problems. Federico Mena Quintero, one of the Novell GNOME guys is one of the people that are working on GNOME performance stuff. He

From: Joerg Roedel <jroedel at suse.de> When an NMI hits in the #VC handler entry code before it switched to another stack, any subsequent #VC exception in the NMI code-path will overwrite the interrupted #VC handlers stack. Make sure this doesn't happen by explicitly adjusting the #VC IST entry in the NMI handler for the time in can cause #VC exceptions. Signed-off-by: Joerg Roedel

From: Joerg Roedel <jroedel at suse.de> When an NMI hits in the #VC handler entry code before it switched to another stack, any subsequent #VC exception in the NMI code-path will overwrite the interrupted #VC handlers stack. Make sure this doesn't happen by explicitly adjusting the #VC IST entry in the NMI handler for the time in can cause #VC exceptions. Signed-off-by: Joerg Roedel

On Tue, Jul 14, 2020 at 02:08:47PM +0200, Joerg Roedel wrote: > @@ -489,6 +490,9 @@ DEFINE_IDTENTRY_RAW(exc_nmi) > this_cpu_write(nmi_cr2, read_cr2()); > nmi_restart: > > + /* Needs to happen before DR7 is accessed */ > + sev_es_ist_enter(regs); > + > this_cpu_write(nmi_dr7, local_db_save()); > > nmi_enter(); > @@ -502,6 +506,8 @@

On Tue, Jul 14, 2020 at 02:08:47PM +0200, Joerg Roedel wrote: > @@ -489,6 +490,9 @@ DEFINE_IDTENTRY_RAW(exc_nmi) > this_cpu_write(nmi_cr2, read_cr2()); > nmi_restart: > > + /* Needs to happen before DR7 is accessed */ > + sev_es_ist_enter(regs); > + > this_cpu_write(nmi_dr7, local_db_save()); > > nmi_enter(); > @@ -502,6 +506,8 @@

From: Tom Lendacky <thomas.lendacky at amd.com> Add the handler for #VC exceptions invoked at runtime. Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com> Signed-off-by: Joerg Roedel <jroedel at suse.de> --- arch/x86/entry/entry_64.S | 4 + arch/x86/include/asm/traps.h | 7 ++ arch/x86/kernel/idt.c | 4 +- arch/x86/kernel/sev-es.c | 167

From: Tom Lendacky <thomas.lendacky at amd.com> Add code to handle #VC exceptions on DR7 register reads and writes. This is needed early because show_regs() reads DR7 to print it out. Under SEV-ES there is currently no support for saving/restoring the DRx registers, but software expects to be able to write to the DR7 register. For now, cache the value written to DR7 and return it on read

On 10/10/2017 09:09 PM, Tetsuo Handa wrote: > Wei Wang wrote: >>> And even if we could remove balloon_lock, you still cannot use >>> __GFP_DIRECT_RECLAIM at xb_set_page(). I think you will need to use >>> "whether it is safe to wait" flag from >>> "[PATCH] virtio: avoid possible OOM lockup at virtballoon_oom_notify()" . >> Without

On 10/11/2017 10:26 AM, Tetsuo Handa wrote: > Wei Wang wrote: >> On 10/10/2017 09:09 PM, Tetsuo Handa wrote: >>> Wei Wang wrote: >>>>> And even if we could remove balloon_lock, you still cannot use >>>>> __GFP_DIRECT_RECLAIM at xb_set_page(). I think you will need to use >>>>> "whether it is safe to wait" flag from

On Tue, Apr 28, 2020 at 05:17:04PM +0200, Joerg Roedel wrote: > +static enum es_result vc_handle_dr7_write(struct ghcb *ghcb, > + struct es_em_ctxt *ctxt) > +{ > + struct sev_es_runtime_data *data = this_cpu_read(runtime_data); > + long val, *reg = vc_insn_get_rm(ctxt); > + enum es_result ret; > + > + if (!reg) > + return ES_DECODE_FAILED; > + > + val =