Any objections/comments on axing out old ATA stack?

[Adrian Chadd]

On 28 March 2013 09:05, Lev Serebryakov <lev at freebsd.org> wrote:

>  Yes:  USB  UMASS. It uses CAM too, and useful for very small systems,
>  like  4MiB  FLASH  and 16MiB RAM (yes, whole system image, kernel and
>  all, should be packed to 4MiB).
>
>  Please note, Adrian speaks about CAM, not only CAM + ATA.

And I'm not at all saying we should keep the old ATA driver around.
I'm just pointing out a set of use cases that most FreeBSD developers
aren't involved with and I'd like to find a way to squeeze it more
efficiently into embedded platforms.

I've never had any noticable performance issues with CAM on my
embedded MIPS boards because it's typically pushing packets. It's just
the resultant binary size of the whole stack that's a problem.

adrian at freefall:~/public_html/ath$ cat AP121-nodebug.txt  | grep scsi
   text	   data	    bss	    dec	    hex	filename

  49372	  10672	     80	  60124	   eadc	scsi_all.o
  21200	   2576	     16	  23792	   5cf0	scsi_da.o
  23288	   1488	     16	  24792	   60d8	scsi_xpt.o
adrian at freefall:~/public_html/ath$ cat AP121-nodebug.txt  | grep cam
   text	   data	    bss	    dec	    hex	filename

   3824	     96	     16	   3936	    f60	cam.o
  13552	    144	     16	  13712	   3590	cam_periph.o
   2344	    144	      0	   2488	    9b8	cam_queue.o
    640	     48	      0	    688	    2b0	cam_sim.o
  40684	    752	    192	  41628	   a29c	cam_xpt.o
adrian at freefall:~/public_html/ath$ cat AP121-nodebug.txt  | grep umass
   text	   data	    bss	    dec	    hex	filename

  22592	   1072	     16	  23680	   5c80	umass.o

adrian at freefall:~/public_html/ath$ cat AP121-nodebug.txt | egrep
'(cam_|umass|scsi_)'
  13552	    144	     16	  13712	   3590	cam_periph.o
   2344	    144	      0	   2488	    9b8	cam_queue.o
    640	     48	      0	    688	    2b0	cam_sim.o
  40684	    752	    192	  41628	   a29c	cam_xpt.o
  49372	  10672	     80	  60124	   eadc	scsi_all.o
  21200	   2576	     16	  23792	   5cf0	scsi_da.o
  23288	   1488	     16	  24792	   60d8	scsi_xpt.o
  22592	   1072	     16	  23680	   5c80	umass.o
adrian at freefall:~/public_html/ath$ cat AP121-nodebug.txt | egrep
'(cam_|umass|scsi_)' | awk '{a+=$4} END {print a}'
190904

It doesn't seem like a lot, but it does add up..



Adrian