Skip to content

R
raspberrypi-kernel

openeuler / raspberrypi-kernel

通知 13
Star 1
Fork 0
R
raspberrypi-kernel
切换分支/标签
  1. 30 11月, 2009 1 次提交
  3. 25 11月, 2009 1 次提交
  5. 24 11月, 2009 3 次提交
    • P
      sh: Apply the sleazy FPU changes for SH-2A FPU as well. · 0f09e197
      由 Paul Mundt 提交于 
      This plugs in the fpu_counter manipulation for the SH-2A side also.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      0f09e197
    • S
      sh: Minor optimisations to FPU handling · d3ea9fa0
      由 Stuart Menefy 提交于 
      A number of small optimisations to FPU handling, in particular:

 - move the task USEDFPU flag from the thread_info flags field (which
   is accessed asynchronously to the thread) to a new status field,
   which is only accessed by the thread itself. This allows locking to
   be removed in most cases, or can be reduced to a preempt_lock().
   This mimics the i386 behaviour.

 - move the modification of regs->sr and thread_info->status flags out
   of save_fpu() to __unlazy_fpu(). This gives the compiler a better
   chance to optimise things, as well as making save_fpu() symmetrical
   with restore_fpu() and init_fpu().

 - implement prepare_to_copy(), so that when creating a thread, we can
   unlazy the FPU prior to copying the thread data structures.

Also make sure that the FPU is disabled while in the kernel, in
particular while booting, and for newly created kernel threads,

In a very artificial benchmark, the execution time for 2500000
context switches was reduced from 50 to 45 seconds.
Signed-off-by: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      d3ea9fa0
    • G
      sh: add sleazy FPU optimization · a0458b07
      由 Giuseppe CAVALLARO 提交于 
      sh port of the sLeAZY-fpu feature currently implemented for some architectures
such us i386.

Right now the SH kernel has a 100% lazy fpu behaviour.
This is of course great for applications that have very sporadic or no FPU use.
However for very frequent FPU users...  you take an extra trap every context
switch.
The patch below adds a simple heuristic to this code: after 5 consecutive
context switches of FPU use, the lazy behavior is disabled and the context
gets restored every context switch.
After 256 switches, this is reset and the 100% lazy behavior is returned.

Tests with LMbench showed no regression.
I saw a little improvement due to the prefetching (~2%).

The tests below also show that, with this sLeazy patch, indeed,
the number of FPU exceptions is reduced.
To test this. I hacked the lat_ctx LMBench to use the FPU a little more.

   sLeasy implementation
   ===========================================
   switch_to calls            |  79326
   sleasy   calls             |  42577
   do_fpu_state_restore  calls|  59232
   restore_fpu   calls        |  59032

   Exceptions:  0x800 (FPU disabled  ): 16604

   100% Leazy (default implementation)
   ===========================================
   switch_to  calls            |  79690
   do_fpu_state_restore calls  |  53299
   restore_fpu  calls          |   53101

   Exceptions: 0x800 (FPU disabled  ):  53273
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      a0458b07
  7. 18 11月, 2009 1 次提交
  9. 12 11月, 2009 3 次提交
  11. 09 11月, 2009 1 次提交
  13. 06 11月, 2009 1 次提交
  15. 05 11月, 2009 5 次提交
  17. 04 11月, 2009 1 次提交
  19. 02 11月, 2009 1 次提交
    • P
      sh: intc: Handle legacy IRQ reservation in vector map. · 45b9deaf
      由 Paul Mundt 提交于 
      Different CPUs will have different starting vectors, with varying
amounts of reserved or unusable vector space prior to the first slot.
This introduces a legacy vector reservation system that inserts itself in
between the CPU vector map registration and the platform specific IRQ
setup. This works fine in practice as the only new vectors that boards
need to establish on their own should be dynamically allocated rather
than arbitrarily assigned. As a plus, this also makes all of the
converted platforms sparseirq ready.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      45b9deaf
  21. 30 10月, 2009 8 次提交
  23. 28 10月, 2009 2 次提交
  25. 27 10月, 2009 4 次提交
  27. 26 10月, 2009 5 次提交
  29. 20 10月, 2009 1 次提交
  31. 19 10月, 2009 2 次提交