| Message ID | 46c6bf61-5669-0de2-163d-64b9a3ce07a7@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/mwait-idle: (remaining) SPR support | expand |
On 02.06.2022 12:26, Jan Beulich wrote: > From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> > > On Sapphire Rapids Xeon (SPR) the C1 and C1E states are basically mutually > exclusive - only one of them can be enabled. By default, 'intel_idle' driver > enables C1 and disables C1E. However, some users prefer to use C1E instead of > C1, because it saves more energy. > > This patch adds a new module parameter ('preferred_cstates') for enabling C1E > and disabling C1. Here is the idea behind it. > > 1. This option has effect only for "mutually exclusive" C-states like C1 and > C1E on SPR. > 2. It does not have any effect on independent C-states, which do not require > other C-states to be disabled (most states on most platforms as of today). > 3. For mutually exclusive C-states, the 'intel_idle' driver always has a > reasonable default, such as enabling C1 on SPR by default. On other > platforms, the default may be different. > 4. Users can override the default using the 'preferred_cstates' parameter. > 5. The parameter accepts the preferred C-states bit-mask, similarly to the > existing 'states_off' parameter. > 6. This parameter is not limited to C1/C1E, and leaves room for supporting > other mutually exclusive C-states, if they come in the future. > > Today 'intel_idle' can only be compiled-in, which means that on SPR, in order > to disable C1 and enable C1E, users should boot with the following kernel > argument: intel_idle.preferred_cstates=4 > > Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Origin: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git da0e58c038e6 > > Enable C1E (if requested) not only on the BSP's socket / package. Alter > command line option to fit our model, and extend it to also accept > string form arguments. > > Signed-off-by: Jan Beulich <jbeulich@suse.com> > --- > v2: Also accept string form arguments for command line option. Restore > C1E-control related enum from Linux, despite our somewhat different > use (and bigger code churn). Any chance of getting an ack here, then also unblocking the 2nd patch? Thanks, Jan > --- a/docs/misc/xen-command-line.pandoc > +++ b/docs/misc/xen-command-line.pandoc > @@ -1885,6 +1885,12 @@ paging controls access to usermode addre > ### ple_window (Intel) > > `= <integer>` > > +### preferred-cstates (x86) > +> `= ( <integer> | List of ( C1 | C1E | C2 | ... )` > + > +This is a mask of C-states which are to be used preferably. This option is > +applicable only on hardware were certain C-states are exclusive of one another. > + > ### psr (Intel) > > `= List of ( cmt:<boolean> | rmid_max:<integer> | cat:<boolean> | cos_max:<integer> | cdp:<boolean> )` > > --- a/xen/arch/x86/cpu/mwait-idle.c > +++ b/xen/arch/x86/cpu/mwait-idle.c > @@ -82,10 +82,29 @@ boolean_param("mwait-idle", opt_mwait_id > > static unsigned int mwait_substates; > > +/* > + * Some platforms come with mutually exclusive C-states, so that if one is > + * enabled, the other C-states must not be used. Example: C1 and C1E on > + * Sapphire Rapids platform. This parameter allows for selecting the > + * preferred C-states among the groups of mutually exclusive C-states - the > + * selected C-states will be registered, the other C-states from the mutually > + * exclusive group won't be registered. If the platform has no mutually > + * exclusive C-states, this parameter has no effect. > + */ > +static unsigned int __ro_after_init preferred_states_mask; > +static char __initdata preferred_states[64]; > +string_param("preferred-cstates", preferred_states); > + > #define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF > /* Reliable LAPIC Timer States, bit 1 for C1 etc. Default to only C1. */ > static unsigned int lapic_timer_reliable_states = (1 << 1); > > +enum c1e_promotion { > + C1E_PROMOTION_PRESERVE, > + C1E_PROMOTION_ENABLE, > + C1E_PROMOTION_DISABLE > +}; > + > struct idle_cpu { > const struct cpuidle_state *state_table; > > @@ -95,7 +114,7 @@ struct idle_cpu { > */ > unsigned long auto_demotion_disable_flags; > bool byt_auto_demotion_disable_flag; > - bool disable_promotion_to_c1e; > + enum c1e_promotion c1e_promotion; > }; > > static const struct idle_cpu *icpu; > @@ -924,6 +943,15 @@ static void cf_check byt_auto_demotion_d > wrmsrl(MSR_MC6_DEMOTION_POLICY_CONFIG, 0); > } > > +static void cf_check c1e_promotion_enable(void *dummy) > +{ > + uint64_t msr_bits; > + > + rdmsrl(MSR_IA32_POWER_CTL, msr_bits); > + msr_bits |= 0x2; > + wrmsrl(MSR_IA32_POWER_CTL, msr_bits); > +} > + > static void cf_check c1e_promotion_disable(void *dummy) > { > u64 msr_bits; > @@ -936,7 +964,7 @@ static void cf_check c1e_promotion_disab > static const struct idle_cpu idle_cpu_nehalem = { > .state_table = nehalem_cstates, > .auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_atom = { > @@ -954,64 +982,64 @@ static const struct idle_cpu idle_cpu_li > > static const struct idle_cpu idle_cpu_snb = { > .state_table = snb_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_byt = { > .state_table = byt_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > .byt_auto_demotion_disable_flag = true, > }; > > static const struct idle_cpu idle_cpu_cht = { > .state_table = cht_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > .byt_auto_demotion_disable_flag = true, > }; > > static const struct idle_cpu idle_cpu_ivb = { > .state_table = ivb_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_ivt = { > .state_table = ivt_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_hsw = { > .state_table = hsw_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_bdw = { > .state_table = bdw_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_skl = { > .state_table = skl_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_skx = { > .state_table = skx_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_icx = { > .state_table = icx_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static struct idle_cpu __read_mostly idle_cpu_spr = { > .state_table = spr_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_avn = { > .state_table = avn_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_knl = { > @@ -1020,17 +1048,17 @@ static const struct idle_cpu idle_cpu_kn > > static const struct idle_cpu idle_cpu_bxt = { > .state_table = bxt_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_dnv = { > .state_table = dnv_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > static const struct idle_cpu idle_cpu_snr = { > .state_table = snr_cstates, > - .disable_promotion_to_c1e = true, > + .c1e_promotion = C1E_PROMOTION_DISABLE, > }; > > #define ICPU(model, cpu) \ > @@ -1241,6 +1269,25 @@ static void __init skx_idle_state_table_ > } > > /* > + * spr_idle_state_table_update - Adjust Sapphire Rapids idle states table. > + */ > +static void __init spr_idle_state_table_update(void) > +{ > + /* Check if user prefers C1E over C1. */ > + if (preferred_states_mask & BIT(2, U)) { > + if (preferred_states_mask & BIT(1, U)) > + /* Both can't be enabled, stick to the defaults. */ > + return; > + > + spr_cstates[0].flags |= CPUIDLE_FLAG_DISABLED; > + spr_cstates[1].flags &= ~CPUIDLE_FLAG_DISABLED; > + > + /* Request enabling C1E using the "C1E promotion" bit. */ > + idle_cpu_spr.c1e_promotion = C1E_PROMOTION_ENABLE; > + } > +} > + > +/* > * mwait_idle_state_table_update() > * > * Update the default state_table for this CPU-id > @@ -1261,6 +1308,9 @@ static void __init mwait_idle_state_tabl > case INTEL_FAM6_SKYLAKE_X: > skx_idle_state_table_update(); > break; > + case INTEL_FAM6_SAPPHIRERAPIDS_X: > + spr_idle_state_table_update(); > + break; > } > } > > @@ -1268,6 +1318,7 @@ static int __init mwait_idle_probe(void) > { > unsigned int eax, ebx, ecx; > const struct x86_cpu_id *id = x86_match_cpu(intel_idle_ids); > + const char *str; > > if (!id) { > pr_debug(PREFIX "does not run on family %d model %d\n", > @@ -1309,6 +1360,39 @@ static int __init mwait_idle_probe(void) > pr_debug(PREFIX "lapic_timer_reliable_states %#x\n", > lapic_timer_reliable_states); > > + str = preferred_states; > + if (isdigit(str[0])) > + preferred_states_mask = simple_strtoul(str, &str, 0); > + else if (str[0]) > + { > + const char *ss; > + > + do { > + const struct cpuidle_state *state = icpu->state_table; > + unsigned int bit = 1; > + > + ss = strchr(str, ','); > + if (!ss) > + ss = strchr(str, '\0'); > + > + for (; state->name[0]; ++state) { > + bit <<= 1; > + if (!cmdline_strcmp(str, state->name)) { > + preferred_states_mask |= bit; > + break; > + } > + } > + if (!state->name[0]) > + break; > + > + str = ss + 1; > + } while (*ss); > + > + str -= str == ss + 1; > + } > + if (str[0]) > + printk("unrecognized \"preferred-cstates=%s\"\n", str); > + > mwait_idle_state_table_update(); > > return 0; > @@ -1400,8 +1484,18 @@ static int cf_check mwait_idle_cpu_init( > if (icpu->byt_auto_demotion_disable_flag) > on_selected_cpus(cpumask_of(cpu), byt_auto_demotion_disable, NULL, 1); > > - if (icpu->disable_promotion_to_c1e) > + switch (icpu->c1e_promotion) { > + case C1E_PROMOTION_DISABLE: > on_selected_cpus(cpumask_of(cpu), c1e_promotion_disable, NULL, 1); > + break; > + > + case C1E_PROMOTION_ENABLE: > + on_selected_cpus(cpumask_of(cpu), c1e_promotion_enable, NULL, 1); > + break; > + > + case C1E_PROMOTION_PRESERVE: > + break; > + } > > return NOTIFY_DONE; > } > >
--- a/docs/misc/xen-command-line.pandoc +++ b/docs/misc/xen-command-line.pandoc @@ -1885,6 +1885,12 @@ paging controls access to usermode addre ### ple_window (Intel) > `= <integer>` +### preferred-cstates (x86) +> `= ( <integer> | List of ( C1 | C1E | C2 | ... )` + +This is a mask of C-states which are to be used preferably. This option is +applicable only on hardware were certain C-states are exclusive of one another. + ### psr (Intel) > `= List of ( cmt:<boolean> | rmid_max:<integer> | cat:<boolean> | cos_max:<integer> | cdp:<boolean> )` --- a/xen/arch/x86/cpu/mwait-idle.c +++ b/xen/arch/x86/cpu/mwait-idle.c @@ -82,10 +82,29 @@ boolean_param("mwait-idle", opt_mwait_id static unsigned int mwait_substates; +/* + * Some platforms come with mutually exclusive C-states, so that if one is + * enabled, the other C-states must not be used. Example: C1 and C1E on + * Sapphire Rapids platform. This parameter allows for selecting the + * preferred C-states among the groups of mutually exclusive C-states - the + * selected C-states will be registered, the other C-states from the mutually + * exclusive group won't be registered. If the platform has no mutually + * exclusive C-states, this parameter has no effect. + */ +static unsigned int __ro_after_init preferred_states_mask; +static char __initdata preferred_states[64]; +string_param("preferred-cstates", preferred_states); + #define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF /* Reliable LAPIC Timer States, bit 1 for C1 etc. Default to only C1. */ static unsigned int lapic_timer_reliable_states = (1 << 1); +enum c1e_promotion { + C1E_PROMOTION_PRESERVE, + C1E_PROMOTION_ENABLE, + C1E_PROMOTION_DISABLE +}; + struct idle_cpu { const struct cpuidle_state *state_table; @@ -95,7 +114,7 @@ struct idle_cpu { */ unsigned long auto_demotion_disable_flags; bool byt_auto_demotion_disable_flag; - bool disable_promotion_to_c1e; + enum c1e_promotion c1e_promotion; }; static const struct idle_cpu *icpu; @@ -924,6 +943,15 @@ static void cf_check byt_auto_demotion_d wrmsrl(MSR_MC6_DEMOTION_POLICY_CONFIG, 0); } +static void cf_check c1e_promotion_enable(void *dummy) +{ + uint64_t msr_bits; + + rdmsrl(MSR_IA32_POWER_CTL, msr_bits); + msr_bits |= 0x2; + wrmsrl(MSR_IA32_POWER_CTL, msr_bits); +} + static void cf_check c1e_promotion_disable(void *dummy) { u64 msr_bits; @@ -936,7 +964,7 @@ static void cf_check c1e_promotion_disab static const struct idle_cpu idle_cpu_nehalem = { .state_table = nehalem_cstates, .auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_atom = { @@ -954,64 +982,64 @@ static const struct idle_cpu idle_cpu_li static const struct idle_cpu idle_cpu_snb = { .state_table = snb_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_byt = { .state_table = byt_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, .byt_auto_demotion_disable_flag = true, }; static const struct idle_cpu idle_cpu_cht = { .state_table = cht_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, .byt_auto_demotion_disable_flag = true, }; static const struct idle_cpu idle_cpu_ivb = { .state_table = ivb_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_ivt = { .state_table = ivt_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_hsw = { .state_table = hsw_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_bdw = { .state_table = bdw_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_skl = { .state_table = skl_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_skx = { .state_table = skx_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_icx = { .state_table = icx_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static struct idle_cpu __read_mostly idle_cpu_spr = { .state_table = spr_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_avn = { .state_table = avn_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_knl = { @@ -1020,17 +1048,17 @@ static const struct idle_cpu idle_cpu_kn static const struct idle_cpu idle_cpu_bxt = { .state_table = bxt_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_dnv = { .state_table = dnv_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; static const struct idle_cpu idle_cpu_snr = { .state_table = snr_cstates, - .disable_promotion_to_c1e = true, + .c1e_promotion = C1E_PROMOTION_DISABLE, }; #define ICPU(model, cpu) \ @@ -1241,6 +1269,25 @@ static void __init skx_idle_state_table_ } /* + * spr_idle_state_table_update - Adjust Sapphire Rapids idle states table. + */ +static void __init spr_idle_state_table_update(void) +{ + /* Check if user prefers C1E over C1. */ + if (preferred_states_mask & BIT(2, U)) { + if (preferred_states_mask & BIT(1, U)) + /* Both can't be enabled, stick to the defaults. */ + return; + + spr_cstates[0].flags |= CPUIDLE_FLAG_DISABLED; + spr_cstates[1].flags &= ~CPUIDLE_FLAG_DISABLED; + + /* Request enabling C1E using the "C1E promotion" bit. */ + idle_cpu_spr.c1e_promotion = C1E_PROMOTION_ENABLE; + } +} + +/* * mwait_idle_state_table_update() * * Update the default state_table for this CPU-id @@ -1261,6 +1308,9 @@ static void __init mwait_idle_state_tabl case INTEL_FAM6_SKYLAKE_X: skx_idle_state_table_update(); break; + case INTEL_FAM6_SAPPHIRERAPIDS_X: + spr_idle_state_table_update(); + break; } } @@ -1268,6 +1318,7 @@ static int __init mwait_idle_probe(void) { unsigned int eax, ebx, ecx; const struct x86_cpu_id *id = x86_match_cpu(intel_idle_ids); + const char *str; if (!id) { pr_debug(PREFIX "does not run on family %d model %d\n", @@ -1309,6 +1360,39 @@ static int __init mwait_idle_probe(void) pr_debug(PREFIX "lapic_timer_reliable_states %#x\n", lapic_timer_reliable_states); + str = preferred_states; + if (isdigit(str[0])) + preferred_states_mask = simple_strtoul(str, &str, 0); + else if (str[0]) + { + const char *ss; + + do { + const struct cpuidle_state *state = icpu->state_table; + unsigned int bit = 1; + + ss = strchr(str, ','); + if (!ss) + ss = strchr(str, '\0'); + + for (; state->name[0]; ++state) { + bit <<= 1; + if (!cmdline_strcmp(str, state->name)) { + preferred_states_mask |= bit; + break; + } + } + if (!state->name[0]) + break; + + str = ss + 1; + } while (*ss); + + str -= str == ss + 1; + } + if (str[0]) + printk("unrecognized \"preferred-cstates=%s\"\n", str); + mwait_idle_state_table_update(); return 0; @@ -1400,8 +1484,18 @@ static int cf_check mwait_idle_cpu_init( if (icpu->byt_auto_demotion_disable_flag) on_selected_cpus(cpumask_of(cpu), byt_auto_demotion_disable, NULL, 1); - if (icpu->disable_promotion_to_c1e) + switch (icpu->c1e_promotion) { + case C1E_PROMOTION_DISABLE: on_selected_cpus(cpumask_of(cpu), c1e_promotion_disable, NULL, 1); + break; + + case C1E_PROMOTION_ENABLE: + on_selected_cpus(cpumask_of(cpu), c1e_promotion_enable, NULL, 1); + break; + + case C1E_PROMOTION_PRESERVE: + break; + } return NOTIFY_DONE; }