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Added detection for big.LITTLE

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Added detection for big.LITTLE aka cpu:s where not all cores have the same frequency like on Intel Alder Lake and newer. The current logic allows a 5% difference in the max frequency due to some reports that those cpu:s doesn't always give back the exact same value (possible due to boosting capability).
This commit is contained in:
Henrik Holst
2023-05-03 21:09:02 +02:00
committed by afayaz-feral
parent ba1c593d0e
commit 51ee251efb
1 changed files with 71 additions and 49 deletions
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120
daemon/gamemode-cpu.c
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@ -50,14 +50,14 @@ static int read_small_file (char *path, char **buf, size_t *buflen)
FILE *f = fopen(path, "r");
if (!f) {
LOG_ERROR("Couldn't open file at %s (%s), will not apply cpu core parking!\n", path, strerror(errno));
LOG_ERROR("Couldn't open file at %s : %s\n", path, strerror(errno));
return 0;
}
ssize_t nread = getline(buf, buflen, f);
if (nread == -1) {
LOG_ERROR("Couldn't read file at %s (%s), will not apply cpu core parking!\n", path, strerror(errno));
LOG_ERROR("Couldn't read file at %s : %s\n", path, strerror(errno));
fclose(f);
return 0;
}
@ -75,47 +75,79 @@ static int read_small_file (char *path, char **buf, size_t *buflen)
static int walk_sysfs (char *cpulist, char **buf, size_t *buflen, GameModeCPUInfo *info)
{
char path[PATH_MAX];
unsigned long long max_cache = 0;
unsigned long long max_cache = 0, max_freq = 0;
long from, to;
cpu_set_t *freq_cores = CPU_ALLOC(info->num_cpu);
char *list = cpulist;
while ((list = parse_cpulist(list, &from, &to))) {
for (long cpu = from; cpu < to + 1; cpu++) {
int ret = snprintf(path, PATH_MAX, "/sys/devices/system/cpu/cpu%ld/cache/index3/size", cpu);
if (ret < 0 || ret >= PATH_MAX) {
LOG_ERROR("snprintf failed, will not apply cpu core parking!\n");
return 0;
}
if (!read_small_file(path, buf, buflen))
return 0;
char *endp;
unsigned long long cache_size = strtoull (*buf, &endp, 10);
if (*endp == 'K') {
cache_size *= 1024;
} else if (*endp == 'M') {
cache_size *= 1024 * 1024;
} else if (*endp == 'G') {
cache_size *= 1024 * 1024 * 1024;
} else if (*endp != '\0') {
LOG_ERROR("cpu L3 cache size (%s) is silly, will not apply cpu core parking!\n", *buf);
return 0;
}
if (cache_size > max_cache) {
max_cache = cache_size;
CPU_ZERO_S(CPU_ALLOC_SIZE(info->num_cpu), info->to_keep);
}
if (cache_size == max_cache)
CPU_SET_S((size_t)cpu, CPU_ALLOC_SIZE(info->num_cpu), info->to_keep);
CPU_SET_S((size_t)cpu, CPU_ALLOC_SIZE(info->num_cpu), info->online);
/* check for L3 cache non-uniformity among the cores */
int ret = snprintf(path, PATH_MAX, "/sys/devices/system/cpu/cpu%ld/cache/index3/size", cpu);
if (ret > 0 && ret < PATH_MAX) {
if (read_small_file(path, buf, buflen)) {
char *endp;
unsigned long long cache_size = strtoull (*buf, &endp, 10);
if (*endp == 'K') {
cache_size *= 1024;
} else if (*endp == 'M') {
cache_size *= 1024 * 1024;
} else if (*endp == 'G') {
cache_size *= 1024 * 1024 * 1024;
} else if (*endp != '\0') {
LOG_MSG("cpu L3 cache size (%s) on core #%ld is silly\n", *buf, cpu);
cache_size = 0;
}
if (cache_size > max_cache) {
max_cache = cache_size;
CPU_ZERO_S(CPU_ALLOC_SIZE(info->num_cpu), info->to_keep);
}
if (cache_size == max_cache)
CPU_SET_S((size_t)cpu, CPU_ALLOC_SIZE(info->num_cpu), info->to_keep);
}
}
/* check for frequency non-uniformity among the cores */
ret = snprintf(path, PATH_MAX, "/sys/devices/system/cpu/cpu%ld/cpufreq/cpuinfo_max_freq", cpu);
if (ret > 0 && ret < PATH_MAX) {
if (read_small_file(path, buf, buflen)) {
unsigned long long freq = strtoull (*buf, NULL, 10);
unsigned long long cutoff = (freq * 5) / 100;
if (freq > max_freq) {
if (max_freq < freq - cutoff)
CPU_ZERO_S(CPU_ALLOC_SIZE(info->num_cpu), freq_cores);
max_freq = freq;
}
if (freq - cutoff >= max_freq)
CPU_SET_S((size_t)cpu, CPU_ALLOC_SIZE(info->num_cpu), freq_cores);
}
}
}
}
if (CPU_EQUAL_S(CPU_ALLOC_SIZE(info->num_cpu), info->online, info->to_keep) || CPU_COUNT_S(CPU_ALLOC_SIZE(info->num_cpu), info->to_keep) == 0) {
LOG_MSG("cpu L3 cache was uniform, this is not a x3D with multiple chiplets\n");
CPU_FREE(info->to_keep);
info->to_keep = freq_cores;
if (CPU_EQUAL_S(CPU_ALLOC_SIZE(info->num_cpu), info->online, info->to_keep) || CPU_COUNT_S(CPU_ALLOC_SIZE(info->num_cpu), info->to_keep) == 0)
LOG_MSG("cpu frequency was uniform, this is not a big.LITTLE type of system\n");
} else {
CPU_FREE(freq_cores);
}
return 1;
}
@ -148,9 +180,6 @@ static int walk_string (char *cpulist, char *config_cpulist, GameModeCPUInfo *in
return 1;
}
/**
* Attempts to identify the current in use CPU information
*/
int game_mode_initialise_cpu(GameModeConfig *config, GameModeCPUInfo **info)
{
/* Verify input, this is programmer error */
@ -237,17 +266,16 @@ int game_mode_initialise_cpu(GameModeConfig *config, GameModeCPUInfo **info)
if (park_or_pin == 0 && CPU_EQUAL_S(CPU_ALLOC_SIZE(new_info->num_cpu), new_info->online, new_info->to_keep)) {
game_mode_free_cpu(&new_info);
LOG_MSG("cpu L3 cache is uniform, will not apply cpu core parking!\n");
LOG_MSG("I can find no reason to perform core parking on this system!\n");
goto error_exit;
}
if (CPU_COUNT_S(CPU_ALLOC_SIZE(new_info->num_cpu), new_info->to_keep) == 0) {
if (CPU_COUNT_S(CPU_ALLOC_SIZE(new_info->num_cpu), new_info->to_keep) < 4) {
game_mode_free_cpu(&new_info);
LOG_MSG("logic or config wanted to park/unpin every single cpu core, will not apply cpu core parking/pinning!\n");
LOG_MSG("logic or config would result in less than 4 active cores, will not apply cpu core parking/pinning!\n");
goto error_exit;
}
/* Give back the new cpu info */
*info = new_info;
early_exit:
@ -289,9 +317,6 @@ static int log_state (char *cpulist, int *pos, const long first, const long last
return 1;
}
/**
* Park the unwanted cpu cores when gamemode is active
*/
int game_mode_park_cpu(const GameModeCPUInfo *info)
{
if (!info || info->park_or_pin == 1)
@ -336,9 +361,6 @@ int game_mode_park_cpu(const GameModeCPUInfo *info)
return 0;
}
/**
* Restore the parked cpu cores when gamemode is disabled
*/
int game_mode_unpark_cpu(const GameModeCPUInfo *info)
{
if (!info || info->park_or_pin == 1)
@ -388,11 +410,12 @@ void game_mode_apply_core_pinning(const GameModeCPUInfo *info, const pid_t clien
if (!info || info->park_or_pin == 0)
return;
LOG_MSG("Pinning process...\n");
if (sched_setaffinity(client, CPU_ALLOC_SIZE(info->num_cpu), info->to_keep) != 0)
LOG_ERROR("Failed to pin process: %s\n", strerror(errno));
}
/* Simply used to free the CPU info object */
void game_mode_free_cpu(GameModeCPUInfo **info)
{
if (!(*info)) {
@ -406,4 +429,3 @@ void game_mode_free_cpu(GameModeCPUInfo **info)
*info = NULL;
}
}