view src/misc/ngx_google_perftools_module.c @ 8759:56dec0d4e5b1 quic

QUIC: avoid excessive buffer allocations in stream output. Previously, when a few bytes were send to a QUIC stream by the application, a 4K buffer was allocated for these bytes. Then a STREAM frame was created and that entire buffer was used as data for that frame. The frame with the buffer were in use up until the frame was acked by client. Meanwhile, when more bytes were send to the stream, more buffers were allocated and assigned as data to newer STREAM frames. In this scenario most buffer memory is unused. Now the unused part of the stream output buffer is available for further stream output while earlier parts of the buffer are waiting to be acked. This is achieved by splitting the output buffer.
author Roman Arutyunyan <arut@nginx.com>
date Fri, 24 Dec 2021 18:13:51 +0300
parents a27e0c7e198c
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>

/*
 * declare Profiler interface here because
 * <google/profiler.h> is C++ header file
 */

int ProfilerStart(u_char* fname);
void ProfilerStop(void);
void ProfilerRegisterThread(void);


static void *ngx_google_perftools_create_conf(ngx_cycle_t *cycle);
static ngx_int_t ngx_google_perftools_worker(ngx_cycle_t *cycle);


typedef struct {
    ngx_str_t  profiles;
} ngx_google_perftools_conf_t;


static ngx_command_t  ngx_google_perftools_commands[] = {

    { ngx_string("google_perftools_profiles"),
      NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      0,
      offsetof(ngx_google_perftools_conf_t, profiles),
      NULL },

      ngx_null_command
};


static ngx_core_module_t  ngx_google_perftools_module_ctx = {
    ngx_string("google_perftools"),
    ngx_google_perftools_create_conf,
    NULL
};


ngx_module_t  ngx_google_perftools_module = {
    NGX_MODULE_V1,
    &ngx_google_perftools_module_ctx,      /* module context */
    ngx_google_perftools_commands,         /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    ngx_google_perftools_worker,           /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static void *
ngx_google_perftools_create_conf(ngx_cycle_t *cycle)
{
    ngx_google_perftools_conf_t  *gptcf;

    gptcf = ngx_pcalloc(cycle->pool, sizeof(ngx_google_perftools_conf_t));
    if (gptcf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc()
     *
     *     gptcf->profiles = { 0, NULL };
     */

    return gptcf;
}


static ngx_int_t
ngx_google_perftools_worker(ngx_cycle_t *cycle)
{
    u_char                       *profile;
    ngx_google_perftools_conf_t  *gptcf;

    gptcf = (ngx_google_perftools_conf_t *)
                ngx_get_conf(cycle->conf_ctx, ngx_google_perftools_module);

    if (gptcf->profiles.len == 0) {
        return NGX_OK;
    }

    profile = ngx_alloc(gptcf->profiles.len + NGX_INT_T_LEN + 2, cycle->log);
    if (profile == NULL) {
        return NGX_OK;
    }

    if (getenv("CPUPROFILE")) {
        /* disable inherited Profiler enabled in master process */
        ProfilerStop();
    }

    ngx_sprintf(profile, "%V.%d%Z", &gptcf->profiles, ngx_pid);

    if (ProfilerStart(profile)) {
        /* start ITIMER_PROF timer */
        ProfilerRegisterThread();

    } else {
        ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_errno,
                      "ProfilerStart(%s) failed", profile);
    }

    ngx_free(profile);

    return NGX_OK;
}


/* ProfilerStop() is called on Profiler destruction */