From 3a004e1fee4ba3d37976c1a9707869acc8d60b55 Mon Sep 17 00:00:00 2001 From: Meng Li Date: Fri, 19 Jan 2024 17:05:01 +0800 Subject: Documentation: amd-pstate: introduce amd-pstate preferred core Introduce amd-pstate preferred core. check preferred core state set by the kernel parameter: $ cat /sys/devices/system/cpu/amd-pstate/prefcore Tested-by: Oleksandr Natalenko Reviewed-by: Wyes Karny Reviewed-by: Mario Limonciello Reviewed-by: Huang Rui Reviewed-by: Perry Yuan Signed-off-by: Meng Li Signed-off-by: Rafael J. Wysocki --- Documentation/admin-guide/pm/amd-pstate.rst | 59 ++++++++++++++++++++++++++++- 1 file changed, 57 insertions(+), 2 deletions(-) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index 9eb26014d34b..0a3aa6b8ffd5 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -300,8 +300,8 @@ platforms. The AMD P-States mechanism is the more performance and energy efficiency frequency management method on AMD processors. -AMD Pstate Driver Operation Modes -================================= +``amd-pstate`` Driver Operation Modes +====================================== ``amd_pstate`` CPPC has 3 operation modes: autonomous (active) mode, non-autonomous (passive) mode and guided autonomous (guided) mode. @@ -353,6 +353,48 @@ is activated. In this mode, driver requests minimum and maximum performance level and the platform autonomously selects a performance level in this range and appropriate to the current workload. +``amd-pstate`` Preferred Core +================================= + +The core frequency is subjected to the process variation in semiconductors. +Not all cores are able to reach the maximum frequency respecting the +infrastructure limits. Consequently, AMD has redefined the concept of +maximum frequency of a part. This means that a fraction of cores can reach +maximum frequency. To find the best process scheduling policy for a given +scenario, OS needs to know the core ordering informed by the platform through +highest performance capability register of the CPPC interface. + +``amd-pstate`` preferred core enables the scheduler to prefer scheduling on +cores that can achieve a higher frequency with lower voltage. The preferred +core rankings can dynamically change based on the workload, platform conditions, +thermals and ageing. + +The priority metric will be initialized by the ``amd-pstate`` driver. The ``amd-pstate`` +driver will also determine whether or not ``amd-pstate`` preferred core is +supported by the platform. + +``amd-pstate`` driver will provide an initial core ordering when the system boots. +The platform uses the CPPC interfaces to communicate the core ranking to the +operating system and scheduler to make sure that OS is choosing the cores +with highest performance firstly for scheduling the process. When ``amd-pstate`` +driver receives a message with the highest performance change, it will +update the core ranking and set the cpu's priority. + +``amd-pstate`` Preferred Core Switch +================================= +Kernel Parameters +----------------- + +``amd-pstate`` peferred core`` has two states: enable and disable. +Enable/disable states can be chosen by different kernel parameters. +Default enable ``amd-pstate`` preferred core. + +``amd_prefcore=disable`` + +For systems that support ``amd-pstate`` preferred core, the core rankings will +always be advertised by the platform. But OS can choose to ignore that via the +kernel parameter ``amd_prefcore=disable``. + User Space Interface in ``sysfs`` - General =========================================== @@ -385,6 +427,19 @@ control its functionality at the system level. They are located in the to the operation mode represented by that string - or to be unregistered in the "disable" case. +``prefcore`` + Preferred core state of the driver: "enabled" or "disabled". + + "enabled" + Enable the ``amd-pstate`` preferred core. + + "disabled" + Disable the ``amd-pstate`` preferred core + + + This attribute is read-only to check the state of preferred core set + by the kernel parameter. + ``cpupower`` tool support for ``amd-pstate`` =============================================== -- cgit v1.2.3 From dfddf34a3f0d45483f5b3e46c2e7bda173796f1b Mon Sep 17 00:00:00 2001 From: Meng Li Date: Fri, 19 Jan 2024 17:05:02 +0800 Subject: Documentation: introduce amd-pstate preferrd core mode kernel command line options amd-pstate driver support enable/disable preferred core. Default enabled on platforms supporting amd-pstate preferred core. Disable amd-pstate preferred core with "amd_prefcore=disable" added to the kernel command line. Signed-off-by: Meng Li Reviewed-by: Mario Limonciello Reviewed-by: Wyes Karny Reviewed-by: Huang Rui Reviewed-by: Perry Yuan Tested-by: Oleksandr Natalenko Signed-off-by: Rafael J. Wysocki --- Documentation/admin-guide/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 31b3a25680d0..522530432548 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -374,6 +374,11 @@ selects a performance level in this range and appropriate to the current workload. + amd_prefcore= + [X86] + disable + Disable amd-pstate preferred core. + amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: , -- cgit v1.2.3 From 4c7dbd85218d6e2ed0495bbaf40c1b1c6bac506b Mon Sep 17 00:00:00 2001 From: Meng Li Date: Mon, 5 Feb 2024 14:03:05 +0800 Subject: Documentation: PM: amd-pstate: Fix section title underline Title under line too short Signed-off-by: Meng Li [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki --- Documentation/admin-guide/pm/amd-pstate.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index 0a3aa6b8ffd5..1e0d101b020a 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -381,7 +381,7 @@ driver receives a message with the highest performance change, it will update the core ranking and set the cpu's priority. ``amd-pstate`` Preferred Core Switch -================================= +===================================== Kernel Parameters ----------------- -- cgit v1.2.3 From 3fec6e5961b77af6a952b77f5c2ea26f7513b216 Mon Sep 17 00:00:00 2001 From: Nikhil V Date: Wed, 14 Feb 2024 13:09:32 +0530 Subject: PM: hibernate: Support to select compression algorithm Currently the default compression algorithm is selected based on compile time options. Introduce a module parameter "hibernate.compressor" to override this behaviour. Different compression algorithms have different characteristics and hibernation may benefit when it uses any of these algorithms, especially when a secondary algorithm(LZ4) offers better decompression speeds over a default algorithm(LZO), which in turn reduces hibernation image restore time. Users can override the default algorithm in two ways: 1) Passing "hibernate.compressor" as kernel command line parameter. Usage: LZO: hibernate.compressor=lzo LZ4: hibernate.compressor=lz4 2) Specifying the algorithm at runtime. Usage: LZO: echo lzo > /sys/module/hibernate/parameters/compressor LZ4: echo lz4 > /sys/module/hibernate/parameters/compressor Currently LZO and LZ4 are the supported algorithms. LZO is the default compression algorithm used with hibernation. Signed-off-by: Nikhil V Signed-off-by: Rafael J. Wysocki --- Documentation/admin-guide/kernel-parameters.txt | 11 +++++ kernel/power/hibernate.c | 57 +++++++++++++++++++++++-- 2 files changed, 65 insertions(+), 3 deletions(-) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 31b3a25680d0..8f7fb911b2cc 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1748,6 +1748,17 @@ (that will set all pages holding image data during restoration read-only). + hibernate.compressor= [HIBERNATION] Compression algorithm to be + used with hibernation. + Format: { lzo | lz4 } + Default: lzo + + lzo: Select LZO compression algorithm to + compress/decompress hibernation image. + + lz4: Select LZ4 compression algorithm to + compress/decompress hibernation image. + highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact size of . This works even on boxes that have no highmem otherwise. This also works to reduce highmem diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 219191d6d0e8..43b1a82e800c 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -47,7 +47,7 @@ dev_t swsusp_resume_device; sector_t swsusp_resume_block; __visible int in_suspend __nosavedata; -static const char *default_compressor = CONFIG_HIBERNATION_DEF_COMP; +static char hibernate_compressor[CRYPTO_MAX_ALG_NAME] = CONFIG_HIBERNATION_DEF_COMP; /* * Compression/decompression algorithm to be used while saving/loading @@ -748,7 +748,7 @@ int hibernate(void) * Query for the compression algorithm support if compression is enabled. */ if (!nocompress) { - strscpy(hib_comp_algo, default_compressor, sizeof(hib_comp_algo)); + strscpy(hib_comp_algo, hibernate_compressor, sizeof(hib_comp_algo)); if (crypto_has_comp(hib_comp_algo, 0, 0) != 1) { pr_err("%s compression is not available\n", hib_comp_algo); return -EOPNOTSUPP; @@ -999,7 +999,7 @@ static int software_resume(void) if (swsusp_header_flags & SF_COMPRESSION_ALG_LZ4) strscpy(hib_comp_algo, COMPRESSION_ALGO_LZ4, sizeof(hib_comp_algo)); else - strscpy(hib_comp_algo, default_compressor, sizeof(hib_comp_algo)); + strscpy(hib_comp_algo, COMPRESSION_ALGO_LZO, sizeof(hib_comp_algo)); if (crypto_has_comp(hib_comp_algo, 0, 0) != 1) { pr_err("%s compression is not available\n", hib_comp_algo); error = -EOPNOTSUPP; @@ -1422,6 +1422,57 @@ static int __init nohibernate_setup(char *str) return 1; } +static const char * const comp_alg_enabled[] = { +#if IS_ENABLED(CONFIG_CRYPTO_LZO) + COMPRESSION_ALGO_LZO, +#endif +#if IS_ENABLED(CONFIG_CRYPTO_LZ4) + COMPRESSION_ALGO_LZ4, +#endif +}; + +static int hibernate_compressor_param_set(const char *compressor, + const struct kernel_param *kp) +{ + unsigned int sleep_flags; + int index, ret; + + sleep_flags = lock_system_sleep(); + + index = sysfs_match_string(comp_alg_enabled, compressor); + if (index >= 0) { + ret = param_set_copystring(comp_alg_enabled[index], kp); + if (!ret) + strscpy(hib_comp_algo, comp_alg_enabled[index], + sizeof(hib_comp_algo)); + } else { + ret = index; + } + + unlock_system_sleep(sleep_flags); + + if (ret) + pr_debug("Cannot set specified compressor %s\n", + compressor); + + return ret; +} + +static const struct kernel_param_ops hibernate_compressor_param_ops = { + .set = hibernate_compressor_param_set, + .get = param_get_string, +}; + +static struct kparam_string hibernate_compressor_param_string = { + .maxlen = sizeof(hibernate_compressor), + .string = hibernate_compressor, +}; + +module_param_cb(compressor, &hibernate_compressor_param_ops, + &hibernate_compressor_param_string, 0644); +MODULE_PARM_DESC(compressor, + "Compression algorithm to be used with hibernation"); + __setup("noresume", noresume_setup); __setup("resume_offset=", resume_offset_setup); __setup("resume=", resume_setup); -- cgit v1.2.3