Company completion very slow

Question

I use company for completion, and it's fast and efficient in OCaml, Tuareg, and Merlin.

However, it is very slow in my C project. For example, it takes more than 10 seconds when it suggests completions for structure, during which I cannot do anything in Emacs.

An example of structure I use in my project :

typedef struct {
  char name[D_NAME_MAXLEN];      /**< name of the disk */
  uint32_t size;   /**< size of the disk */
  uint32_t npart;   /**< number of partitions */
  uint32_t part[D_PARTMAX];    /**< parition sizes */
} d_stat;

Then I have a d_stat pointer caled d_stat and after typing typing dstat-> it stops for a looong long time, even sometimes it bugs...

Same thing with the macros, I have some macros :

OPT_SIZE
OPT_LONG_SIZE
OPT_FORCE
OPT_LONG_FORCE
OPT_NAME
OPT_LONG_NAME
etc...

And when I type OPT_ it stops like above.

How can I speed up company completion when it gets this slow? Right now, it is not usable.

I'm using (global-company-mode) in my init file.

tree of the project looks like :

syscp
├── bin
│   ├── disk.tfs
│   ├── libll.so
│   ├── libtfs.so
│   ├── tfs_analyze
│   ├── tfs_create
│   ├── tfs_format
│   └── tfs_partition
├── dev
│   └── device.tfs
├── disk.tfs
├── doc
│   └── config
├── ld
├── lib
│   ├── block0.h
│   ├── block.c
│   ├── block.h
│   ├── error.c
│   ├── error.h
│   ├── ll.c
│   ├── ll.h
│   ├── tfs.c
│   ├── tfs.h
│   ├── utils.c
│   └── utils.h
├── Makefile
├── obj
│   ├── block.o
│   ├── error.o
│   ├── libblock.o
│   ├── liberror.o
│   ├── libll.o
│   ├── libtfs.o
│   ├── ll.o
│   └── utils.o
├── README
├── setup.sh
└── src
    ├── default.h
    ├── tfs_analyze.c
    ├── tfs_create.c
    ├── tfs_format.c
    └── tfs_partition.c

7 directories, 39 files