if (result)
return result;
- if (state == ACPI_STATE_UNKNOWN)
+ if (state == ACPI_STATE_UNKNOWN) {
state = ACPI_STATE_D0;
-
- result = acpi_device_set_power(device, state);
- if (!result && state_p)
+ result = acpi_device_set_power(device, state);
+ if (result)
+ return result;
+ } else {
+ if (device->power.flags.power_resources) {
+ /*
+ * We don't need to really switch the state, bu we need
+ * to update the power resources' reference counters.
+ */
+ result = acpi_power_transition(device, state);
+ if (result)
+ return result;
+ }
+ device->power.state = state;
+ }
+ if (state_p)
*state_p = state;
- return result;
+ return 0;
}
EXPORT_SYMBOL_GPL(acpi_bus_update_power);
return AE_OK;
}
-int __init acpi_dock_init(void)
+void __init acpi_dock_init(void)
{
if (acpi_disabled)
- return 0;
+ return;
/* look for dock stations and bays */
acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
if (!dock_station_count) {
pr_info(PREFIX "No dock devices found.\n");
- return 0;
+ return;
}
register_acpi_bus_notifier(&dock_acpi_notifier);
pr_info(PREFIX "%s: %d docks/bays found\n",
ACPI_DOCK_DRIVER_DESCRIPTION, dock_station_count);
- return 0;
}
{
struct acpi_device *device = cdev->devdata;
int result;
- int acpi_state;
+ int acpi_state = ACPI_STATE_D0;
if (!device)
return -EINVAL;
if (resource->ref_count++) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
- "Power resource [%s] already on",
+ "Power resource [%s] already on\n",
resource->name));
} else {
result = __acpi_power_on(resource);
if (!resource->ref_count) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
- "Power resource [%s] already off",
+ "Power resource [%s] already off\n",
resource->name));
return 0;
}
static const char *dummy_hid = "device";
-static LIST_HEAD(acpi_device_list);
static LIST_HEAD(acpi_bus_id_list);
static DEFINE_MUTEX(acpi_scan_lock);
static LIST_HEAD(acpi_scan_handlers_list);
switch (state) {
case CPUFREQ_PRECHANGE:
- if (WARN(policy->transition_ongoing,
+ if (WARN(policy->transition_ongoing ==
+ cpumask_weight(policy->cpus),
"In middle of another frequency transition\n"))
return;
- policy->transition_ongoing = true;
+ policy->transition_ongoing++;
/* detect if the driver reported a value as "old frequency"
* which is not equal to what the cpufreq core thinks is
"No frequency transition in progress\n"))
return;
- policy->transition_ongoing = false;
+ policy->transition_ongoing--;
adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
struct kobject kobj;
struct completion kobj_unregister;
- bool transition_ongoing; /* Tracks transition status */
+ int transition_ongoing; /* Tracks transition status */
};
#define CPUFREQ_ADJUST (0)
utils/helpers/sysfs.o utils/helpers/misc.o utils/helpers/cpuid.o \
utils/helpers/pci.o utils/helpers/bitmask.o \
utils/idle_monitor/nhm_idle.o utils/idle_monitor/snb_idle.o \
+ utils/idle_monitor/hsw_ext_idle.o \
utils/idle_monitor/amd_fam14h_idle.o utils/idle_monitor/cpuidle_sysfs.o \
utils/idle_monitor/mperf_monitor.o utils/idle_monitor/cpupower-monitor.o \
utils/cpupower.o utils/cpufreq-info.o utils/cpufreq-set.o \
- utils/cpupower-set.o utils/cpupower-info.o utils/cpuidle-info.o
+ utils/cpupower-set.o utils/cpupower-info.o utils/cpuidle-info.o \
+ utils/cpuidle-set.o
UTIL_SRC := $(UTIL_OBJS:.o=.c)
kernel frequency driver periodically cleared aperf/mperf registers in those
kernels.
-.SS "Nehalem" "SandyBridge"
+.SS "Nehalem" "SandyBridge" "HaswellExtended"
Intel Core and Package sleep state counters.
Threads (hyperthreaded cores) may not be able to enter deeper core states if
its sibling is utilized.
Deepest package sleep states may in reality show up as machine/platform wide
sleep states and can only be entered if all cores are idle. Look up Intel
manuals (some are provided in the References section) for further details.
+The monitors are named after the CPU family where the sleep state capabilities
+got introduced and may not match exactly the CPU name of the platform.
+For example an IvyBridge processor has sleep state capabilities which got
+introduced in Nehalem and SandyBridge processor families.
+Thus on an IvyBridge processor one will get Nehalem and SandyBridge sleep
+state monitors.
+HaswellExtended extra package sleep state capabilities are available only in a
+specific Haswell (family 0x45) and probably also other future processors.
.SS "Fam_12h" "Fam_14h"
AMD laptop and desktop processor (family 12h and 14h) sleep state counters.
extern int cmd_info(int argc, const char **argv);
extern int cmd_freq_set(int argc, const char **argv);
extern int cmd_freq_info(int argc, const char **argv);
+extern int cmd_idle_set(int argc, const char **argv);
extern int cmd_idle_info(int argc, const char **argv);
extern int cmd_monitor(int argc, const char **argv);
static void cpuidle_cpu_output(unsigned int cpu, int verbose)
{
- int idlestates, idlestate;
+ unsigned int idlestates, idlestate;
char *tmp;
printf(_ ("Analyzing CPU %d:\n"), cpu);
if (idlestates == 0) {
printf(_("CPU %u: No idle states\n"), cpu);
return;
- } else if (idlestates <= 0) {
- printf(_("CPU %u: Can't read idle state info\n"), cpu);
- return;
}
+
printf(_("Number of idle states: %d\n"), idlestates);
printf(_("Available idle states:"));
for (idlestate = 0; idlestate < idlestates; idlestate++) {
return;
for (idlestate = 0; idlestate < idlestates; idlestate++) {
+ int disabled = sysfs_is_idlestate_disabled(cpu, idlestate);
+ /* Disabled interface not supported on older kernels */
+ if (disabled < 0)
+ disabled = 0;
tmp = sysfs_get_idlestate_name(cpu, idlestate);
if (!tmp)
continue;
- printf("%s:\n", tmp);
+ printf("%s%s:\n", tmp, (disabled) ? " (DISABLED) " : "");
free(tmp);
tmp = sysfs_get_idlestate_desc(cpu, idlestate);
static void proc_cpuidle_cpu_output(unsigned int cpu)
{
long max_allowed_cstate = 2000000000;
- int cstates, cstate;
+ unsigned int cstate, cstates;
cstates = sysfs_get_idlestate_count(cpu);
if (cstates == 0) {
- /*
- * Go on and print same useless info as you'd see with
- * cat /proc/acpi/processor/../power
- * printf(_("CPU %u: No C-states available\n"), cpu);
- * return;
- */
- } else if (cstates <= 0) {
- printf(_("CPU %u: Can't read C-state info\n"), cpu);
+ printf(_("CPU %u: No C-states info\n"), cpu);
return;
}
- /* printf("Cstates: %d\n", cstates); */
printf(_("active state: C0\n"));
printf(_("max_cstate: C%u\n"), cstates-1);
--- /dev/null
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <string.h>
+#include <ctype.h>
+
+#include <getopt.h>
+
+#include "cpufreq.h"
+#include "helpers/helpers.h"
+#include "helpers/sysfs.h"
+
+static struct option info_opts[] = {
+ { .name = "disable", .has_arg = required_argument, .flag = NULL, .val = 'd'},
+ { .name = "enable", .has_arg = required_argument, .flag = NULL, .val = 'e'},
+ { },
+};
+
+
+int cmd_idle_set(int argc, char **argv)
+{
+ extern char *optarg;
+ extern int optind, opterr, optopt;
+ int ret = 0, cont = 1, param = 0, idlestate = 0;
+ unsigned int cpu = 0;
+
+ do {
+ ret = getopt_long(argc, argv, "d:e:", info_opts, NULL);
+ if (ret == -1)
+ break;
+ switch (ret) {
+ case '?':
+ param = '?';
+ cont = 0;
+ break;
+ case 'd':
+ if (param) {
+ param = -1;
+ cont = 0;
+ break;
+ }
+ param = ret;
+ idlestate = atoi(optarg);
+ break;
+ case 'e':
+ if (param) {
+ param = -1;
+ cont = 0;
+ break;
+ }
+ param = ret;
+ idlestate = atoi(optarg);
+ break;
+ case -1:
+ cont = 0;
+ break;
+ }
+ } while (cont);
+
+ switch (param) {
+ case -1:
+ printf(_("You can't specify more than one "
+ "output-specific argument\n"));
+ exit(EXIT_FAILURE);
+ case '?':
+ printf(_("invalid or unknown argument\n"));
+ exit(EXIT_FAILURE);
+ }
+
+ /* Default is: set all CPUs */
+ if (bitmask_isallclear(cpus_chosen))
+ bitmask_setall(cpus_chosen);
+
+ for (cpu = bitmask_first(cpus_chosen);
+ cpu <= bitmask_last(cpus_chosen); cpu++) {
+
+ if (!bitmask_isbitset(cpus_chosen, cpu))
+ continue;
+
+ switch (param) {
+
+ case 'd':
+ ret = sysfs_idlestate_disable(cpu, idlestate, 1);
+ if (ret == 0)
+ printf(_("Idlestate %u disabled on CPU %u\n"), idlestate, cpu);
+ else if (ret == -1)
+ printf(_("Idlestate %u not available on CPU %u\n"),
+ idlestate, cpu);
+ else if (ret == -2)
+ printf(_("Idlestate disabling not supported by kernel\n"));
+ else
+ printf(_("Idlestate %u not disabled on CPU %u\n"),
+ idlestate, cpu);
+ break;
+ case 'e':
+ ret = sysfs_idlestate_disable(cpu, idlestate, 0);
+ if (ret == 0)
+ printf(_("Idlestate %u enabled on CPU %u\n"), idlestate, cpu);
+ else if (ret == -1)
+ printf(_("Idlestate %u not available on CPU %u\n"),
+ idlestate, cpu);
+ else if (ret == -2)
+ printf(_("Idlestate enabling not supported by kernel\n"));
+ else
+ printf(_("Idlestate %u not enabled on CPU %u\n"),
+ idlestate, cpu);
+ break;
+ default:
+ /* Not reachable with proper args checking */
+ printf(_("Invalid or unknown argument\n"));
+ exit(EXIT_FAILURE);
+ break;
+ }
+ }
+ return EXIT_SUCCESS;
+}
#include "helpers/helpers.h"
#include "helpers/bitmask.h"
-struct cmd_struct {
- const char *cmd;
- int (*main)(int, const char **);
- int needs_root;
-};
-
#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
static int cmd_help(int argc, const char **argv);
static void print_help(void);
+struct cmd_struct {
+ const char *cmd;
+ int (*main)(int, const char **);
+ int needs_root;
+};
+
static struct cmd_struct commands[] = {
{ "frequency-info", cmd_freq_info, 0 },
{ "frequency-set", cmd_freq_set, 1 },
{ "idle-info", cmd_idle_info, 0 },
+ { "idle-set", cmd_idle_set, 1 },
{ "set", cmd_set, 1 },
{ "info", cmd_info, 0 },
{ "monitor", cmd_monitor, 0 },
return value;
}
+/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+
+
/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
+/*
+ * helper function to check whether a file under "../cpuX/cpuidle/stateX/" dir
+ * exists.
+ * For example the functionality to disable c-states was introduced in later
+ * kernel versions, this function can be used to explicitly check for this
+ * feature.
+ *
+ * returns 1 if the file exists, 0 otherwise.
+ */
+unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
+ unsigned int idlestate,
+ const char *fname)
+{
+ char path[SYSFS_PATH_MAX];
+ struct stat statbuf;
+
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+ cpu, idlestate, fname);
+ if (stat(path, &statbuf) != 0)
+ return 0;
+ return 1;
+}
+
/*
* helper function to read file from /sys into given buffer
* fname is a relative path under "cpuX/cpuidle/stateX/" dir
return (unsigned int) numread;
}
+/*
+ * helper function to write a new value to a /sys file
+ * fname is a relative path under "../cpuX/cpuidle/cstateY/" dir
+ *
+ * Returns the number of bytes written or 0 on error
+ */
+static
+unsigned int sysfs_idlestate_write_file(unsigned int cpu,
+ unsigned int idlestate,
+ const char *fname,
+ const char *value, size_t len)
+{
+ char path[SYSFS_PATH_MAX];
+ int fd;
+ ssize_t numwrite;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
+ cpu, idlestate, fname);
+
+ fd = open(path, O_WRONLY);
+ if (fd == -1)
+ return 0;
+
+ numwrite = write(fd, value, len);
+ if (numwrite < 1) {
+ close(fd);
+ return 0;
+ }
+
+ close(fd);
+
+ return (unsigned int) numwrite;
+}
+
/* read access to files which contain one numeric value */
enum idlestate_value {
IDLESTATE_POWER,
IDLESTATE_LATENCY,
IDLESTATE_TIME,
+ IDLESTATE_DISABLE,
MAX_IDLESTATE_VALUE_FILES
};
[IDLESTATE_POWER] = "power",
[IDLESTATE_LATENCY] = "latency",
[IDLESTATE_TIME] = "time",
+ [IDLESTATE_DISABLE] = "disable",
};
static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,
return result;
}
+/*
+ * Returns:
+ * 1 if disabled
+ * 0 if enabled
+ * -1 if idlestate is not available
+ * -2 if disabling is not supported by the kernel
+ */
+int sysfs_is_idlestate_disabled(unsigned int cpu,
+ unsigned int idlestate)
+{
+ if (sysfs_get_idlestate_count(cpu) < idlestate)
+ return -1;
+
+ if (!sysfs_idlestate_file_exists(cpu, idlestate,
+ idlestate_value_files[IDLESTATE_DISABLE]))
+ return -2;
+ return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_DISABLE);
+}
+
+/*
+ * Pass 1 as last argument to disable or 0 to enable the state
+ * Returns:
+ * 0 on success
+ * negative values on error, for example:
+ * -1 if idlestate is not available
+ * -2 if disabling is not supported by the kernel
+ * -3 No write access to disable/enable C-states
+ */
+int sysfs_idlestate_disable(unsigned int cpu,
+ unsigned int idlestate,
+ unsigned int disable)
+{
+ char value[SYSFS_PATH_MAX];
+ int bytes_written;
+
+ if (sysfs_get_idlestate_count(cpu) < idlestate)
+ return -1;
+
+ if (!sysfs_idlestate_file_exists(cpu, idlestate,
+ idlestate_value_files[IDLESTATE_DISABLE]))
+ return -2;
+
+ snprintf(value, SYSFS_PATH_MAX, "%u", disable);
+
+ bytes_written = sysfs_idlestate_write_file(cpu, idlestate, "disable",
+ value, sizeof(disable));
+ if (bytes_written)
+ return 0;
+ return -3;
+}
+
unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
- unsigned int idlestate)
+ unsigned int idlestate)
{
return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_LATENCY);
}
* Negativ in error case
* Zero if cpuidle does not export any C-states
*/
-int sysfs_get_idlestate_count(unsigned int cpu)
+unsigned int sysfs_get_idlestate_count(unsigned int cpu)
{
char file[SYSFS_PATH_MAX];
struct stat statbuf;
extern unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen);
+extern unsigned int sysfs_idlestate_file_exists(unsigned int cpu,
+ unsigned int idlestate,
+ const char *fname);
+
extern int sysfs_is_cpu_online(unsigned int cpu);
+extern int sysfs_is_idlestate_disabled(unsigned int cpu,
+ unsigned int idlestate);
+extern int sysfs_idlestate_disable(unsigned int cpu, unsigned int idlestate,
+ unsigned int disable);
extern unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
unsigned int idlestate);
extern unsigned long sysfs_get_idlestate_usage(unsigned int cpu,
unsigned int idlestate);
extern char *sysfs_get_idlestate_desc(unsigned int cpu,
unsigned int idlestate);
-extern int sysfs_get_idlestate_count(unsigned int cpu);
+extern unsigned int sysfs_get_idlestate_count(unsigned int cpu);
extern char *sysfs_get_cpuidle_governor(void);
extern char *sysfs_get_cpuidle_driver(void);
--- /dev/null
+/*
+ * (C) 2010,2011 Thomas Renninger <trenn@suse.de>, Novell Inc.
+ *
+ * Licensed under the terms of the GNU GPL License version 2.
+ *
+ * Based on SandyBridge monitor. Implements the new package C-states
+ * (PC8, PC9, PC10) coming with a specific Haswell (family 0x45) CPU.
+ */
+
+#if defined(__i386__) || defined(__x86_64__)
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "helpers/helpers.h"
+#include "idle_monitor/cpupower-monitor.h"
+
+#define MSR_PKG_C8_RESIDENCY 0x00000630
+#define MSR_PKG_C9_RESIDENCY 0x00000631
+#define MSR_PKG_C10_RESIDENCY 0x00000632
+
+#define MSR_TSC 0x10
+
+enum intel_hsw_ext_id { PC8 = 0, PC9, PC10, HSW_EXT_CSTATE_COUNT,
+ TSC = 0xFFFF };
+
+static int hsw_ext_get_count_percent(unsigned int self_id, double *percent,
+ unsigned int cpu);
+
+static cstate_t hsw_ext_cstates[HSW_EXT_CSTATE_COUNT] = {
+ {
+ .name = "PC8",
+ .desc = N_("Processor Package C8"),
+ .id = PC8,
+ .range = RANGE_PACKAGE,
+ .get_count_percent = hsw_ext_get_count_percent,
+ },
+ {
+ .name = "PC9",
+ .desc = N_("Processor Package C9"),
+ .desc = N_("Processor Package C2"),
+ .id = PC9,
+ .range = RANGE_PACKAGE,
+ .get_count_percent = hsw_ext_get_count_percent,
+ },
+ {
+ .name = "PC10",
+ .desc = N_("Processor Package C10"),
+ .id = PC10,
+ .range = RANGE_PACKAGE,
+ .get_count_percent = hsw_ext_get_count_percent,
+ },
+};
+
+static unsigned long long tsc_at_measure_start;
+static unsigned long long tsc_at_measure_end;
+static unsigned long long *previous_count[HSW_EXT_CSTATE_COUNT];
+static unsigned long long *current_count[HSW_EXT_CSTATE_COUNT];
+/* valid flag for all CPUs. If a MSR read failed it will be zero */
+static int *is_valid;
+
+static int hsw_ext_get_count(enum intel_hsw_ext_id id, unsigned long long *val,
+ unsigned int cpu)
+{
+ int msr;
+
+ switch (id) {
+ case PC8:
+ msr = MSR_PKG_C8_RESIDENCY;
+ break;
+ case PC9:
+ msr = MSR_PKG_C9_RESIDENCY;
+ break;
+ case PC10:
+ msr = MSR_PKG_C10_RESIDENCY;
+ break;
+ case TSC:
+ msr = MSR_TSC;
+ break;
+ default:
+ return -1;
+ };
+ if (read_msr(cpu, msr, val))
+ return -1;
+ return 0;
+}
+
+static int hsw_ext_get_count_percent(unsigned int id, double *percent,
+ unsigned int cpu)
+{
+ *percent = 0.0;
+
+ if (!is_valid[cpu])
+ return -1;
+
+ *percent = (100.0 *
+ (current_count[id][cpu] - previous_count[id][cpu])) /
+ (tsc_at_measure_end - tsc_at_measure_start);
+
+ dprint("%s: previous: %llu - current: %llu - (%u)\n",
+ hsw_ext_cstates[id].name, previous_count[id][cpu],
+ current_count[id][cpu], cpu);
+
+ dprint("%s: tsc_diff: %llu - count_diff: %llu - percent: %2.f (%u)\n",
+ hsw_ext_cstates[id].name,
+ (unsigned long long) tsc_at_measure_end - tsc_at_measure_start,
+ current_count[id][cpu] - previous_count[id][cpu],
+ *percent, cpu);
+
+ return 0;
+}
+
+static int hsw_ext_start(void)
+{
+ int num, cpu;
+ unsigned long long val;
+
+ for (num = 0; num < HSW_EXT_CSTATE_COUNT; num++) {
+ for (cpu = 0; cpu < cpu_count; cpu++) {
+ hsw_ext_get_count(num, &val, cpu);
+ previous_count[num][cpu] = val;
+ }
+ }
+ hsw_ext_get_count(TSC, &tsc_at_measure_start, 0);
+ return 0;
+}
+
+static int hsw_ext_stop(void)
+{
+ unsigned long long val;
+ int num, cpu;
+
+ hsw_ext_get_count(TSC, &tsc_at_measure_end, 0);
+
+ for (num = 0; num < HSW_EXT_CSTATE_COUNT; num++) {
+ for (cpu = 0; cpu < cpu_count; cpu++) {
+ is_valid[cpu] = !hsw_ext_get_count(num, &val, cpu);
+ current_count[num][cpu] = val;
+ }
+ }
+ return 0;
+}
+
+struct cpuidle_monitor intel_hsw_ext_monitor;
+
+static struct cpuidle_monitor *hsw_ext_register(void)
+{
+ int num;
+
+ if (cpupower_cpu_info.vendor != X86_VENDOR_INTEL
+ || cpupower_cpu_info.family != 6)
+ return NULL;
+
+ switch (cpupower_cpu_info.model) {
+ case 0x45: /* HSW */
+ break;
+ default:
+ return NULL;
+ }
+
+ is_valid = calloc(cpu_count, sizeof(int));
+ for (num = 0; num < HSW_EXT_CSTATE_COUNT; num++) {
+ previous_count[num] = calloc(cpu_count,
+ sizeof(unsigned long long));
+ current_count[num] = calloc(cpu_count,
+ sizeof(unsigned long long));
+ }
+ intel_hsw_ext_monitor.name_len = strlen(intel_hsw_ext_monitor.name);
+ return &intel_hsw_ext_monitor;
+}
+
+void hsw_ext_unregister(void)
+{
+ int num;
+ free(is_valid);
+ for (num = 0; num < HSW_EXT_CSTATE_COUNT; num++) {
+ free(previous_count[num]);
+ free(current_count[num]);
+ }
+}
+
+struct cpuidle_monitor intel_hsw_ext_monitor = {
+ .name = "HaswellExtended",
+ .hw_states = hsw_ext_cstates,
+ .hw_states_num = HSW_EXT_CSTATE_COUNT,
+ .start = hsw_ext_start,
+ .stop = hsw_ext_stop,
+ .do_register = hsw_ext_register,
+ .unregister = hsw_ext_unregister,
+ .needs_root = 1,
+ .overflow_s = 922000000 /* 922337203 seconds TSC overflow
+ at 20GHz */
+};
+#endif /* defined(__i386__) || defined(__x86_64__) */
DEF(amd_fam14h)
DEF(intel_nhm)
DEF(intel_snb)
+DEF(intel_hsw_ext)
DEF(mperf)
#endif
DEF(cpuidle_sysfs)
case 0x2D: /* SNB Xeon */
case 0x3A: /* IVB */
case 0x3E: /* IVB Xeon */
+ case 0x3C: /* HSW */
+ case 0x3F: /* HSW */
+ case 0x45: /* HSW */
+ case 0x46: /* HSW */
break;
default:
return NULL;
projects / cascardo / linux.git / commitdiff