SDL2 CreateTextureFromSurface slow down - c

Question

im doing a graphic interface in SDL2 but if i create the renderer with the flags SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC i get a notable slowdown in comparation with the flag SDL_RENDERER_SOFTWARE what i think shouldn't be possible.
I can't use SDL_RENDERER_SOFTWARE because i need enable VSYNC for avoid the tearing and i need double buffer for that.
Actually i realize that the bottleneck is with the function SDL_CreateTextureFromSurface().
Like my code is pretty big i'll try to explain it instead of past everything here:
Initialize SDL and create a SDL_Surface named screen_surface with SDL_CreateRGBSurface with the same size than my window where ill blit any other surface.
I draw a big square in the middle of that surface with SDL_FillRect and draw a rack inside that square using two times SDL_FillRect for draw two squares, one 2 pixels more big than the next one and like that simulate a empty square (i know i can do the same with SDL_RenderDrawRect but i think is more optimal draw in a surface instead of the Render) for every cell of the rack until i have 4096 cells;
now using SDL_TTF i write info in each cell for that i use TTF_RenderUTF8_Blended for get a surface for each cell and i use SDL_BlitSurface for 'fusion' this surfaces with the screen_surface
And finally i want to go through the big square illuminating the cells that are being cheked for that i use SDL_FillRect for draw a little square that travel throught the rack.
Finally i use the SDL_CreateTextureFromSurface for transform screen_surface in screen_texture followed for SDL_RenderCopy and SDL_RenderPresent
This five steps are inside of the main while with the event management and following the recomendations in the SDL_API i do SDL_RenderClear each loop for redraw everything another time.
Said all this how i said at the begining i realise that the bottleneck is step 5 independent from the another steps because if i take the steps 2 and 3 and i do them before the while leaving inside the while only the creation of the rack illumination on a black window (cause im not drawing anything) i get the same slowdown. Only if i manage to draw things without use textures the velocity increase notably.
There are my questions:
Why could this happening? Teorically use double buffering shouldn't be faster than use Software Renderer?
There is any form to simulate vsync in Software Renderer?
Can i Render a Surface without build a Texture?
PD: I have read a bunch of post around the internet and im gonna answer some typical questions: i reutilize the screen_surface, i can't reutilize the surface that TTF returns, im creating and destroying the texture each loop (cause i think i can not reutilize it).
I let here my code
int main(int ac, char **av)
{
t_data data;
init_data(&data) /* initialize SDL */
ft_ini_font(data); /* Initialize TTF */
ft_ini_interface(data);
main_loop(&data);
ft_quit_graphics(data); /* Close SDL and TTF */
free(data);
return (0);
}
void main_loop(t_data *data)
{
while (data->running)
{
events(data);
SDL_BlitSurface(data->rack_surface, NULL, data->screen_surface, &(SDL_Rect){data->rack_x, data->rack_y, data->rack_w, data->rack_h}); /* Insert the rack in the screen_surface */
ft_write_info(data);
ft_illum_celd(data);
set_back_to_front(data);
}
}
void ft_ini_interface(t_data *data)
{
data->screen_surface = SDL_CreateRGBSurface(0, data->w, data->h, 32, RED_MASK, GREEN_MASK, BLUE_MASK, ALPHA_MASK)
...
/* stuff for calculate rack dims */
...
data->rack_surface = generate_rack_surface(data);
}
void generate_rack_surface(t_data *data)
{
int i;
int j;
int k;
data->rack_surface = SDL_CreateRGBSurface(0, data->rack_w, data->rack_h, 32, RED_MASK, GREEN_MASK, BLUE_MASK, ALPHA_MASK);
SDL_FillRect(Graph->rack, NULL, 0x3D3D33FF);
...
/* ini i, j, k for drawn the rack properly */
...
while (all cells not drawn)
{
if (k && !i)
{
data->celd_y += Graph->data->celd_h - 1;
data->celd_x = 0;
k--;
}
SDL_FillRect(data->rack, &(SDL_Rect){data->celd_x - 1, data->celd_y - 1, data->celd_w + 2, data->celd_h + 2}, 0x1C1C15FF))
SDL_FillRect(data->rack, &(SDL_Rect){data->celd_x, data->celd_y, data->celd_w, data->celd_h}, 0x3D3D33FF)
data->celd_x += data->celd_w - 1;
i--;
}
}
void ft_write_info(t_data *data)
{
SDL_Color color;
char *info;
while (all info not written)
{
color = take_color(); /*take the color of the info (only 4 ifs) */
info = take_info(data); /*take info from a source using malloc*/
surf_byte = TTF_RenderUTF8_Blended(data->font, info, color);
...
/*stuf for take the correct possition in the rack */
...
SDL_BlitSurface(surf_byte, NULL, Graph->screen.screen, &(SDL_Rect){data->info_x, data->info_y, data->celd.w, data->celd.h});
SDL_FreeSurface(surf_byte);
free(info);
}
void ft_illum_celd(t_data *data)
{
int color;
SDL_Rect illum;
illum = next_illum(data) /* return a SDL_Rect with the position of the info being read */
SDL_FillRect(data->screen_surface, &pc, color);
}
void set_back_to_front(t_data *data)
{
SDL_Texture *texture;
texture = SDL_CreateTextureFromSurface(data->Renderer, data->screen_surface);
SDL_RenderCopy(data->Renderer, texture, NULL, NULL);
SDL_DestroyTexture(texture);
SDL_RenderPresent(data->Renderer);
SDL_RenderClear(data->Renderer);
}