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Merged
Syllo merged 6 commits into from
Feb 8, 2026
Merged

Snapshot Enhancements #439

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0f7ba08
Add interval mode to snapshot
Steve-Tech Feb 7, 2026
dc8345b
Add loop snapshot mode
Steve-Tech Feb 7, 2026
1e6061f
Fix invalid JSON in snapshot
Steve-Tech Feb 7, 2026
f3c5203
Snapshot with delay by default
Syllo Feb 8, 2026
b6b6939
Encode/decode usage and processes in snapshot
Syllo Feb 8, 2026
2c47bc1
Fix json cmdline indent
Syllo Feb 8, 2026
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2 changes: 0 additions & 2 deletions src/extract_gpuinfo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,9 +21,7 @@

#include <ctype.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "nvtop/extract_gpuinfo.h"
#include "nvtop/extract_gpuinfo_common.h"
Expand Down
156 changes: 146 additions & 10 deletions src/interface.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2095,14 +2095,14 @@ bool show_information_messages(unsigned num_messages, const char **messages) {
}

void print_snapshot(struct list_head *devices, bool use_fahrenheit_option) {
gpuinfo_populate_static_infos(devices);
gpuinfo_refresh_dynamic_info(devices);
struct gpu_info *device;

printf("[\n");
list_for_each_entry(device, devices, list) {
const char *indent_level_two = " ";
const char *indent_level_four = " ";
const char *indent_level_six = " ";
const char *indent_level_eight = " ";

const char *device_name_field = "device_name";
const char *gpu_clock_field = "gpu_clock";
Expand Down Expand Up @@ -2173,26 +2173,162 @@ void print_snapshot(struct list_head *devices, bool use_fahrenheit_option) {
else
printf("%s\"%s\": null,\n", indent_level_four, gpu_util_field);

// Encode / Decode
if (device->static_info.encode_decode_shared) {
printf("%s\"encode_decode\": ", indent_level_four);
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, decoder_rate))
printf("\"%u%%\",\n", device->dynamic_info.decoder_rate);
else
printf("null,\n");
} else {
printf("%s\"encode\": ", indent_level_four);
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, encoder_rate))
printf("\"%u%%\",\n", device->dynamic_info.encoder_rate);
else
printf("null,\n");
printf("%s\"decode\": ", indent_level_four);
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, decoder_rate))
printf("\"%u%%\",\n", device->dynamic_info.decoder_rate);
else
printf("null,\n");
}

// Memory Utilization
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, mem_util_rate))
printf("%s\"%s\": \"%u%%\"\n", indent_level_four, mem_util_field, device->dynamic_info.mem_util_rate);
printf("%s\"%s\": \"%u%%\",\n", indent_level_four, mem_util_field, device->dynamic_info.mem_util_rate);
else
printf("%s\"%s\": null\n", indent_level_four, mem_util_field);
printf("%s\"%s\": null,\n", indent_level_four, mem_util_field);
// Memory Total
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, total_memory))
printf("%s\"%s\": \"%llu\"\n", indent_level_four, mem_total_field, device->dynamic_info.total_memory);
printf("%s\"%s\": \"%llu\",\n", indent_level_four, mem_total_field, device->dynamic_info.total_memory);
else
printf("%s\"%s\": null\n", indent_level_four, mem_total_field);
printf("%s\"%s\": null,\n", indent_level_four, mem_total_field);
// Memory Used
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, used_memory))
printf("%s\"%s\": \"%llu\"\n", indent_level_four, mem_used_field, device->dynamic_info.used_memory);
printf("%s\"%s\": \"%llu\",\n", indent_level_four, mem_used_field, device->dynamic_info.used_memory);
else
printf("%s\"%s\": null\n", indent_level_four, mem_used_field);
printf("%s\"%s\": null,\n", indent_level_four, mem_used_field);
// Memory Available
if (GPUINFO_DYNAMIC_FIELD_VALID(&device->dynamic_info, free_memory))
printf("%s\"%s\": \"%llu\"\n", indent_level_four, mem_free_field, device->dynamic_info.free_memory);
printf("%s\"%s\": \"%llu\",\n", indent_level_four, mem_free_field, device->dynamic_info.free_memory);
else
printf("%s\"%s\": null\n", indent_level_four, mem_free_field);
printf("%s\"%s\": null,\n", indent_level_four, mem_free_field);

// Processes
printf("%s\"processes\" : [\n", indent_level_four);
for (unsigned i = 0; i < device->processes_count; ++i) {
struct gpu_process *proc = &device->processes[i];
printf("%s{\n", indent_level_six);

// PID
printf("%s\"pid\": \"%d\",\n", indent_level_eight, proc->pid);

printf("%s\"cmdline\": \"", indent_level_eight);
for (char *li = proc->cmdline; *li != '\0'; li++) {
// We need to escape some characters for for json strings
if (*li == '\n') {
printf("\\n");
continue;
} else if (*li == '\b') {
printf("\\b");
continue;
} else if (*li == '\f') {
printf("\\f");
continue;
} else if (*li == '\r') {
printf("\\r");
continue;
} else if (*li == '\t') {
printf("\\t");
continue;
}
// escaping backslash and quotes
if (*li == '\\' || *li == '"')
printf("\\");
printf("%c", *li);
}
printf("\",\n");

printf("%s\"kind\": ", indent_level_eight);
if (proc->type != gpu_process_unknown) {
printf("\"");
switch (proc->type) {
case gpu_process_graphical:
printf("graphic");
break;
case gpu_process_compute:
printf("compute");
break;
case gpu_process_graphical_compute:
printf("graphic & compute");
break;
default:
printf("N/A");
break;
}
printf("\"");
} else {
printf("null");
}
printf(",\n");

// GPU memory usage
printf("%s\"user\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, user_name))
printf("\"%s\",\n", proc->user_name);
else
printf("null,\n");

// GPU usage
printf("%s\"gpu_usage\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, gpu_usage))
printf("\"%u%%\",\n", proc->gpu_usage);
else
printf("null,\n");

// GPU memory usage
printf("%s\"gpu_mem_bytes_alloc\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, gpu_memory_usage))
printf("\"%llu\",\n", proc->gpu_memory_usage);
else
printf("null,\n");

// GPU memory usage
printf("%s\"gpu_mem_usage\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, gpu_memory_percentage))
printf("\"%u%%\",\n", proc->gpu_memory_percentage);
else
printf("null,\n");

// Encode usage
if (device->static_info.encode_decode_shared) {
// (Notice: no comma at the end as it's the last field here)
printf("%s\"encode_decode\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, decode_usage))
printf("\"%u%%\"\n", proc->decode_usage);
else
printf("null\n");
} else {
printf("%s\"encode\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, encode_usage))
printf("\"%u%%\",\n", proc->encode_usage);
else
printf("null,\n");
// (Notice: no comma at the end as it's the last field here)
printf("%s\"decode\": ", indent_level_eight);
if (GPUINFO_PROCESS_FIELD_VALID(proc, decode_usage))
printf("\"%u%%\"\n", proc->decode_usage);
else
printf("null\n");
}

printf("%s}", indent_level_six);
if (i != device->processes_count - 1)
printf(",");
printf("\n");
}
// (Notice: no comma at the end as it's the last field here)
printf("%s]\n", indent_level_four);

if (device->list.next == devices)
printf("%s}\n", indent_level_two);
Expand Down
41 changes: 37 additions & 4 deletions src/nvtop.c
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <locale.h>
Expand Down Expand Up @@ -74,7 +75,8 @@ static const char helpstring[] = "Available options:\n"
"(default 30s, negative = always on screen)\n"
" -h --help : Print help and exit\n"
" -s --snapshot : Output the current gpu stats without ncurses"
"(useful for scripting)\n";
"(useful for scripting)\n"
" -l --loop : Output the current gpu stats without ncurses in a loop\n";

static const char versionString[] = "nvtop version " NVTOP_VERSION_STRING;

Expand All @@ -92,10 +94,11 @@ static const struct option long_opts[] = {
{.name = "no-processes", .has_arg = no_argument, .flag = NULL, .val = 'P'},
{.name = "reverse-abs", .has_arg = no_argument, .flag = NULL, .val = 'r'},
{.name = "snapshot", .has_arg = no_argument, .flag = NULL, .val = 's'},
{.name = "loop", .has_arg = no_argument, .flag = NULL, .val = 'l'},
{0, 0, 0, 0},
};

static const char opts[] = "hvd:c:CfE:pPris";
static const char opts[] = "hvd:c:CfE:pPrisl";

int main(int argc, char **argv) {
(void)setlocale(LC_CTYPE, "");
Expand All @@ -111,6 +114,7 @@ int main(int argc, char **argv) {
bool encode_decode_timer_option_set = false;
bool show_gpu_info_bar = false;
bool show_snapshot = false;
bool loop_snapshot = false;
double encode_decode_hide_time = -1.;
char *custom_config_file_path = NULL;
while (true) {
Expand Down Expand Up @@ -174,6 +178,9 @@ int main(int argc, char **argv) {
case 's':
show_snapshot = true;
break;
case 'l':
loop_snapshot = true;
break;
case ':':
case '?':
switch (optopt) {
Expand Down Expand Up @@ -226,8 +233,34 @@ int main(int argc, char **argv) {
return EXIT_SUCCESS;
}

if (show_snapshot) {
print_snapshot(&monitoredGpus, use_fahrenheit_option);
if (show_snapshot || loop_snapshot) {
gpuinfo_populate_static_infos(&monitoredGpus);

// Always do a refresh followed by a short sleep to have valid cycle based
// metrics
gpuinfo_refresh_dynamic_info(&monitoredGpus);
gpuinfo_refresh_processes(&monitoredGpus);
gpuinfo_utilisation_rate(&monitoredGpus);
// Default to 0.1 sec
if (!update_interval_option_set)
update_interval_option = 100;

do {
#if _POSIX_C_SOURCE >= 199309L
struct timespec tv = {.tv_sec = update_interval_option / 1000,
.tv_nsec = (update_interval_option % 1000) * 1000000};
nanosleep(&tv, &tv);
#else
int sec = update_interval_option / 1000;
sleep(sec > 0 ? sec : 1);
#endif
gpuinfo_refresh_dynamic_info(&monitoredGpus);
gpuinfo_refresh_processes(&monitoredGpus);
gpuinfo_utilisation_rate(&monitoredGpus);
gpuinfo_fix_dynamic_info_from_process_info(&monitoredGpus);
print_snapshot(&monitoredGpus, use_fahrenheit_option);
} while (loop_snapshot && !signal_exit);

gpuinfo_shutdown_info_extraction(&monitoredGpus);
return EXIT_SUCCESS;
}
Expand Down