Re: [PATCH i-g-t v7 4/5] tools/gputop.src/gputop: Enable support for multiple GPUs and instances

Purkait, Soham
2026-02-18T16:23:39Z

Hi Vinay,

On 13-02-2026 04:58, Belgaumkar, Vinay wrote:
>
> On 1/30/2026 1:53 AM, Soham Purkait wrote:
>> Introduce vendor-agnostic support for handling multiple GPUs and
>> instances in gputop. Improve the tool's adaptability to various GPU
>> configurations.
>>
>> v1:
>>   - Refactor GPUTOP into a vendor-agnostic tool. (Lucas)
>> v2:
>>   - Cosmetic changes. (Riana)
>>   - Avoid three level indentation. (Riana)
>> v3:
>>   - Add device filter to populate the array of cards for
>>     all supported drivers. (Zbigniew)
>> v4:
>>   - Add user message for running without root privileges. (Kamil)
>> v5:
>>   - Add support for GPU client-only busyness on unsupported
>>     drivers as a fallback mechanism. (Kamil)
>> v6:
>>   - Remove unused dependencies and headers. (Kamil)
>>
>> Signed-off-by: Soham Purkait <soham.purkait@intel.com>
>> ---
>>   tools/gputop.src/gputop.c    | 278 +++++++++++++++++++++++++++++------
>>   tools/gputop.src/meson.build |   2 +-
>>   tools/meson.build            |   3 +-
>>   3 files changed, 240 insertions(+), 43 deletions(-)
>>
>> diff --git a/tools/gputop.src/gputop.c b/tools/gputop.src/gputop.c
>> index f577a1750..7d4515f8f 100644
>> --- a/tools/gputop.src/gputop.c
>> +++ b/tools/gputop.src/gputop.c
>> @@ -1,6 +1,6 @@
>>   // SPDX-License-Identifier: MIT
>>   /*
>> - * Copyright © 2023 Intel Corporation
>> + * Copyright © 2023-2025 Intel Corporation
>>    */
>>     #include <assert.h>
>> @@ -14,66 +14,145 @@
>>   #include <math.h>
>>   #include <poll.h>
>>   #include <signal.h>
>> +#include <stdbool.h>
>>   #include <stdint.h>
>>   #include <stdio.h>
>>   #include <stdlib.h>
>>   #include <string.h>
>>   #include <sys/ioctl.h>
>>   #include <sys/stat.h>
>> +#include <sys/sysmacros.h>
>>   #include <sys/types.h>
>> -#include <unistd.h>
>>   #include <termios.h>
>> -#include <sys/sysmacros.h>
>> -#include <stdbool.h>
>> +#include <unistd.h>
>>   -#include "igt_core.h"
>>   #include "igt_drm_clients.h"
>>   #include "igt_drm_fdinfo.h"
>>   #include "igt_profiling.h"
>> -#include "drmtest.h"
>> +#include "xe_gputop.h"
>> +
>> +/**
>> + * Supported Drivers
>> + *
>> + * Adhere to the following requirements when implementing support
>> for the
>> + * new driver:
>> + * @drivers: Update drivers[] with driver string.
>> + * @sizeof_gputop_obj: Update this function as per new driver
>> support included.
>> + * @operations: Update the respective operations of the new driver:
>> + * gputop_init,
>> + * discover_engines,
>> + * pmu_init,
>> + * pmu_sample,
>> + * print_engines,
>> + * clean_up
>> + * @per_driver_contexts: Update per_driver_contexts[] array of type
>> "struct gputop_driver" with the
>> + * initial values.
>> + */
>> +static const char * const drivers[] = {
>> +    "xe",
>> +    /* Keep the last one as NULL */
>> +    NULL
>> +};
>> +
>> +static size_t sizeof_gputop_obj(int driver_num)
>> +{
>> +    switch (driver_num) {
>> +    case 0:
> Might be worthwhile using an enum like INTEL_XE_DRIVER instead of
> hardcoded values.
Sure.
>> +        return sizeof(struct xe_gputop);
>> +    default:
>> +        fprintf(stderr,
>> +            "Driver number does not exist.\n");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +}
>> +
>> +/**
>> + * Supported operations on driver instances. Update the ops[] array for
>> + * each individual driver specific function. Maintain the sequence
>> as per
>> + * drivers[] array.
>> + */
>> +struct device_operations ops[] = {
>> +    {
>> +        xe_gputop_init,
>> +        xe_populate_engines,
>> +        xe_pmu_init,
>> +        xe_pmu_sample,
>> +        xe_print_engines,
>> +        xe_clean_up
>> +    }
>> +};
>> +
>> +/*
>> + * per_driver_contexts[] array of type struct gputop_driver which
>> keeps track of the devices
>> + * and related info discovered per driver.
>> + */
>> +struct gputop_driver per_driver_contexts[] = {
> This is already per driver, no need to add that in the name? just
> driver_context or pci_driver_context? Also, where is gputop_driver
> struct defined? (Didn't find it in this patch set)
In my view this array is indexed by driver, keeping "per_driver_" avoids
the confusion. gputop_driver is defined in tools/gputop/utils.h (not
included in this patch).
>> +    {false, 0, NULL}
>> +};
>>     enum utilization_type {
>>       UTILIZATION_TYPE_ENGINE_TIME,
>>       UTILIZATION_TYPE_TOTAL_CYCLES,
>>   };
>>   -static const char *bars[] = { " ", "▏", "▎", "▍", "▌", "▋", "▊",
>> "▉", "█" };
>> -
>> -#define ANSI_HEADER "\033[7m"
>> -#define ANSI_RESET "\033[0m"
>> -
>> -static void n_spaces(const unsigned int n)
>> +static void gputop_clean_up(void)
>>   {
>> -    unsigned int i;
>> -
>> -    for (i = 0; i < n; i++)
>> -        putchar(' ');
>> +    for (int i = 0; drivers[i]; i++) {
>> +        ops[i].clean_up(per_driver_contexts[i].instances,
>> per_driver_contexts[i].len);
>> +        free(per_driver_contexts[i].instances);
>> +        per_driver_contexts[i].device_present = false;
>> +        per_driver_contexts[i].len = 0;
>> +    }
>>   }
>>   -static void print_percentage_bar(double percent, int max_len)
>> +static int find_driver(struct igt_device_card *card)
> should be find_pci_driver?
Seems like "find_driver" is more appropriate. This is finding the driver
index but not using any "pci only" condition.
>>   {
>> -    int bar_len, i, len = max_len - 1;
>> -    const int w = 8;
>> -
>> -    len -= printf("|%5.1f%% ", percent);
>> -
>> -    /* no space left for bars, do what we can */
>> -    if (len < 0)
>> -        len = 0;
>> -
>> -    bar_len = ceil(w * percent * len / 100.0);
>> -    if (bar_len > w * len)
>> -        bar_len = w * len;
>> +    for (int i = 0; drivers[i]; i++) {
>> +        if (strcmp(drivers[i], card->driver) == 0)
>> +            return i;
>> +    }
>> +    return -1;
>> +}
>>   -    for (i = bar_len; i >= w; i -= w)
>> -        printf("%s", bars[w]);
>> -    if (i)
>> -        printf("%s", bars[i]);
>> +static int populate_device_instances(const char *filter)
>> +{
>> +    struct igt_device_card *cards = NULL;
>> +    struct igt_device_card *card_inplace = NULL;
>> +    struct gputop_driver *driver_entry =  NULL;
>> +    int driver_no;
> should this be driver_num or driver_id?
Sure.
>> +    int count, final_count = 0;
>> +
>> +    count = igt_device_card_match_all(filter, &cards);
>> +    for (int j = 0; j < count; j++) {
>> +        if (strcmp(cards[j].subsystem, "pci") != 0)
>> +            continue;
>>   -    len -= (bar_len + (w - 1)) / w;
>> -    n_spaces(len);
>> +        driver_no = find_driver(&cards[j]);
>> +        if (driver_no < 0)
>> +            continue;
>>   -    putchar('|');
>> +        driver_entry = &per_driver_contexts[driver_no];
>> +        if (!driver_entry->device_present)
>> +            driver_entry->device_present = true;
> is this check only for reassignment of device_present or should it
> include the below statements as well?
This check  sets device_present to true only once if at least one device
for that specific driver is found.
>> +        driver_entry->len++;
>> +        driver_entry->instances = realloc(driver_entry->instances,
>> +                          driver_entry->len *
>> sizeof_gputop_obj(driver_no));
> should this be renamed to driver_entry->engine_instances so we are
> clear about which instances this refers to?

This instance is not exactly the engine instance. It represents a device
of a specific driver. If there are multiple devices of a specific driver
then there should be equal number of such instances and so the function
is named as "populate_device_instances". It is documented where
gputop_driver is defined.

Thanks,
Soham

>> +        if (!driver_entry->instances) {
>> +            fprintf(stderr,
>> +                "Device instance realloc failed (%s)\n",
>> +                strerror(errno));
>> +            exit(EXIT_FAILURE);
>> +        }
>
> should these be under the conditional if check above as well? Or will
> we end up incrementing len twice and duplicate realloc? Unless this
> refers to driver instances?
>
> Thanks,
>
> Vinay.
>
>> +        card_inplace = (struct igt_device_card *)
>> +                calloc(1, sizeof(struct igt_device_card));
>> +        memcpy(card_inplace, &cards[j], sizeof(struct
>> igt_device_card));
>> +        ops[driver_no].gputop_init(driver_entry->instances,
>> (driver_entry->len - 1),
>> +            card_inplace);
>> +        final_count++;
>> +    }
>> +    if (count)
>> +        free(cards);
>> +    return final_count;
>>   }
>>     static int
>> @@ -335,6 +414,28 @@ struct gputop_args {
>>       unsigned long delay_usec;
>>   };
>>   +static void countdown(const char *msg, const int start_sec)
>> +{
>> +    struct pollfd pfd;
>> +    int i, ret;
>> +    char ch;
>> +
>> +    for (i = start_sec; i > 0; i--) {
>> +        printf("\r%s%d... second(s)", msg, i);
>> +        fflush(stdout);
>> +
>> +        pfd.fd = STDIN_FILENO;
>> +        pfd.events = POLLIN;
>> +
>> +        ret = poll(&pfd, 1, 1000);
>> +        if (ret > 0 && (pfd.revents & POLLIN)) {
>> +            while ((ch = getchar()) != '\n' && ch != EOF)
>> +                continue;
>> +            return;
>> +        }
>> +    }
>> +}
>> +
>>   static void help(char *full_path)
>>   {
>>       const char *short_program_name = strrchr(full_path, '/');
>> @@ -349,7 +450,32 @@ static void help(char *full_path)
>>              "Options:\n"
>>              "\t-h, --help                show this help\n"
>>              "\t-d, --delay =SEC[.TENTHS] iterative delay as SECS
>> [.TENTHS]\n"
>> -           "\t-n, --iterations =NUMBER  number of executions\n"
>> +           "\t-n, --iterations =NUMBER  number of executions\n\n"
>> +           "Running without root:\n"
>> +           "\tAs a non-root user, CAP_PERFMON or perf_event_paranoid
>> is required to\n"
>> +           "\taccess engine busyness\n"
>> +           "\t" ANSI_HEADER "Steps to run without root (using
>> CAP_PERFMON):"
>> +        ANSI_RESET "\n"
>> +           "\tcd /path/to/igt-gpu-tools/\n"
>> +           "\tsudo setcap cap_perfmon=+ep $(pwd)/build/tools/gputop\n"
>> +           "\tsudo sh -c \"echo $(pwd)/build/lib >
>> /etc/ld.so.conf.d/lib-igt.conf\"\n"
>> +           "\tsudo ldconfig\n"
>> +           "\t" ANSI_HEADER "Steps to revert once done:" ANSI_RESET
>> "\n"
>> +           "\tsudo setcap cap_perfmon=-ep $(pwd)/build/tools/gputop\n"
>> +           "\tsudo rm /etc/ld.so.conf.d/lib-igt.conf\n"
>> +           "\tsudo ldconfig\n"
>> +           "\n"
>> +           "\t" ANSI_HEADER "Steps to run without root (using
>> perf_event_paranoid):"
>> +           ANSI_RESET "\n"
>> +           "\t\033[32m# Save current perf_event_paranoid
>> value\033[0m\n"
>> +           "\torig_val=$(sysctl -n kernel.perf_event_paranoid)\n"
>> +           "\tsudo sysctl -w kernel.perf_event_paranoid=-1\n"
>> +           "\t" ANSI_HEADER "Steps to revert once done:" ANSI_RESET
>> "\n"
>> +           "\t\033[32m# Restore original value\033[0m\n"
>> +           "\tsudo sysctl -w kernel.perf_event_paranoid=$orig_val\n\n"
>> +           "\tFor details, see 'Perf events and tool security':\n"
>> +           "\thttps://www.kernel.org/doc/html/"
>> +           "latest/admin-guide/perf-security.html\n\n"
>>              , short_program_name);
>>   }
>>   @@ -417,9 +543,12 @@ int main(int argc, char **argv)
>>       struct igt_profiled_device *profiled_devices = NULL;
>>       struct igt_drm_clients *clients = NULL;
>>       int con_w = -1, con_h = -1;
>> +    bool is_root;
>>       int ret;
>>       long n;
>>   +    is_root = (geteuid() == 0);
>> +
>>       ret = parse_args(argc, argv, &args);
>>       if (ret < 0)
>>           return EXIT_FAILURE;
>> @@ -428,6 +557,53 @@ int main(int argc, char **argv)
>>         n = args.n_iter;
>>       period_us = args.delay_usec;
>> +    populate_device_instances("device:subsystem=pci,card=all");
>> +
>> +    for (int i = 0; drivers[i]; i++) {
>> +        if (!per_driver_contexts[i].device_present)
>> +            continue;
>> +
>> +        for (int j = 0; j < per_driver_contexts[i].len; j++) {
>> +            if
>> (!ops[i].init_engines(per_driver_contexts[i].instances, j)) {
>> +                fprintf(stderr,
>> +                    "Failed to initialize engines! (%s)\n",
>> +                    strerror(errno));
>> +                    gputop_clean_up();
>> +                return EXIT_FAILURE;
>> +            }
>> +            ret = ops[i].pmu_init(per_driver_contexts[i].instances, j);
>> +
>> +            if (ret) {
>> +                if (errno == EACCES && !is_root) {
>> +                    fprintf(stderr,
>> +                        "\n"
>> +                        "Running without root privileges.\n"
>> +                        "Engine busyness may not be available "
>> +                        "without root privileges.\n"
>> +                        "See \"--help\" to enable engine "
>> +                        "busyness without root.\n\n");
>> +                    igt_devices_free();
>> +                    gputop_clean_up();
>> +                    countdown("Resuming with only gpu client "
>> +                          "busyness in ", 5);
>> +                } else {
>> +                    fprintf(stderr,
>> +                        "Failed to initialize PMU! (%s)\n",
>> +                        strerror(errno));
>> +                    igt_devices_free();
>> +                    gputop_clean_up();
>> +                    return EXIT_FAILURE;
>> +                }
>> +            }
>> +        }
>> +    }
>> +
>> +    for (int i = 0; drivers[i]; i++) {
>> +        for (int j = 0;
>> +             per_driver_contexts[i].device_present && j <
>> per_driver_contexts[i].len;
>> +             j++)
>> +            ops[i].pmu_sample(per_driver_contexts[i].instances, j);
>> +    }
>>         clients = igt_drm_clients_init(NULL);
>>       if (!clients)
>> @@ -449,22 +625,42 @@ int main(int argc, char **argv)
>>         while ((n != 0) && !stop_top) {
>>           struct igt_drm_client *c, *prevc = NULL;
>> -        int i, engine_w = 0, lines = 0;
>> +        int k, engine_w = 0, lines = 0;
>>             igt_drm_clients_scan(clients, NULL, NULL, 0, NULL, 0);
>> +
>> +        for (int i = 0; drivers[i]; i++) {
>> +            for (int j = 0;
>> +                 per_driver_contexts[i].device_present &&
>> +                 j < per_driver_contexts[i].len;
>> +                 j++)
>> + ops[i].pmu_sample(per_driver_contexts[i].instances, j);
>> +        }
>> +
>>           igt_drm_clients_sort(clients, client_cmp);
>>             update_console_size(&con_w, &con_h);
>>           clrscr();
>>   +        for (int i = 0; drivers[i]; i++) {
>> +            for (int j = 0;
>> +                 per_driver_contexts[i].device_present &&
>> +                 j < per_driver_contexts[i].len;
>> +                 j++) {
>> +                lines =
>> ops[i].print_engines(per_driver_contexts[i].instances, j,
>> +                             lines, con_w, con_h);
>> +            }
>> +        }
>> +
>>           if (!clients->num_clients) {
>> -            const char *msg = " (No GPU clients yet. Start workload
>> to see stats)";
>> +            const char *msg;
>>   +            msg = " (No GPU clients yet. Start workload to see
>> stats)";
>>               printf(ANSI_HEADER "%-*s" ANSI_RESET "\n",
>>                      (int)(con_w - strlen(msg) - 1), msg);
>>           }
>>   -        igt_for_each_drm_client(clients, c, i) {
>> +        igt_for_each_drm_client(clients, c, k) {
>>               assert(c->status != IGT_DRM_CLIENT_PROBE);
>>               if (c->status != IGT_DRM_CLIENT_ALIVE)
>>                   break; /* Active clients are first in the array. */
>> @@ -488,11 +684,11 @@ int main(int argc, char **argv)
>>       }
>>         igt_drm_clients_free(clients);
>> +    gputop_clean_up();
>>         if (profiled_devices != NULL) {
>>           igt_devices_configure_profiling(profiled_devices, false);
>>           igt_devices_free_profiling(profiled_devices);
>>       }
>> -
>>       return 0;
>>   }
>> diff --git a/tools/gputop.src/meson.build b/tools/gputop.src/meson.build
>> index ec39f4c7a..e95657fca 100644
>> --- a/tools/gputop.src/meson.build
>> +++ b/tools/gputop.src/meson.build
>> @@ -1 +1 @@
>> -gputop_src = files('gputop.c')
>> +gputop_src = files('gputop.c', 'utils.c', 'xe_gputop.c')
>> diff --git a/tools/meson.build b/tools/meson.build
>> index 521607a4c..caca57d0e 100644
>> --- a/tools/meson.build
>> +++ b/tools/meson.build
>> @@ -123,4 +123,5 @@ subdir('gputop.src')
>>   executable('gputop', sources : gputop_src,
>>          install : true,
>>          install_rpath : bindir_rpathdir,
>> -       dependencies :
>> [lib_igt_drm_clients,lib_igt_drm_fdinfo,lib_igt_profiling,math],)
>> +       dependencies :
>> [lib_igt_perf,lib_igt_device_scan,lib_igt_drm_clients,
>> +                  lib_igt_drm_fdinfo,lib_igt_profiling,math],)