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  1. 14 2月, 2007 5 次提交
  3. 09 2月, 2007 1 次提交
    • E
      [TG3]: Avoid an expensive divide. · 6b31a515
      由 Eric Dumazet 提交于 
      During an oprofile session of linux-2.6.20 on a dual opteron system, I noticed
an expensive divide was done in tg3_poll().

I am using gcc-4.1.1, so the following comment from drivers/net/tg3.c seems
over-optimistic :

/* Do not place this n-ring entries value into the tp struct itself,
  * we really want to expose these constants to GCC so that modulo et
  * al.  operations are done with shifts and masks instead of with
  * hw multiply/modulo instructions.  Another solution would be to
  * replace things like '% foo' with '& (foo - 1)'.
  */
#define TG3_RX_RCB_RING_SIZE(tp)        \
         ((tp->tg3_flags2 & TG3_FLG2_5705_PLUS) ?  512 : 1024)

Assembly code before patch :
(oprofile results included)
   6434  0.0088 :ffffffff803684b9:       mov    0x6f0(%r15),%eax
    587 8.0e-04 :ffffffff803684c0:       and    $0x40000,%eax
   2170  0.0030 :ffffffff803684c5:       cmp    $0x1,%eax
                :ffffffff803684c8:       lea    0x1(%r13),%eax
                :ffffffff803684cc:       sbb    %ecx,%ecx
   2051  0.0028 :ffffffff803684ce:       xor    %edx,%edx
                :ffffffff803684d0:       and    $0x200,%ecx
     20 2.7e-05 :ffffffff803684d6:       add    $0x200,%ecx
   1986  0.0027 :ffffffff803684dc:       div    %ecx
103427  0.1410 :ffffffff803684de:       cmp    %edx,0xffffffffffffff7c(%rbp)

Assembly code after the suggested patch :

ffffffff803684b9:           mov    0x6f0(%r15),%eax
ffffffff803684c0:           and    $0x40000,%eax
ffffffff803684c5:           cmp    $0x1,%eax
ffffffff803684c8:           sbb    %eax,%eax
ffffffff803684ca:           inc    %r13d
ffffffff803684cd:           and    $0x200,%eax
ffffffff803684d2:           add    $0x1ff,%eax
ffffffff803684d7:           and    %eax,%r13d
ffffffff803684da:           cmp    %r13d,0xffffffffffffff7c(%rbp)
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Acked-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6b31a515
  5. 06 2月, 2007 1 次提交
  7. 09 1月, 2007 1 次提交
  9. 18 12月, 2006 5 次提交
  11. 07 12月, 2006 7 次提交
  13. 22 11月, 2006 2 次提交
  15. 16 11月, 2006 2 次提交
  17. 08 11月, 2006 1 次提交
  19. 06 11月, 2006 1 次提交
    • M
      [TG3]: Fix 2nd ifup failure on 5752M. · 36da4d86
      由 Michael Chan 提交于 
      This fixes a bug reported in:

http://bugzilla.kernel.org/show_bug.cgi?id=7438

tg3_close() turns off the PHY if WoL and ASF are both disabled.  On
the next tg3_open(), some devices such as the 5752M will not be
brought up correctly without a PHY reset early in the reset sequence.
The PHY clock is needed for some internal MAC blocks to function
correctly.

This problem is fixed by always resetting the PHY early in
tg3_reset_hw() when it is called from tg3_open() or tg3_resume().
tg3_setup_phy() can then be called later in the sequence without the
reset_phy parameter set to 1, since the PHY reset is already done.

Update version to 3.68.
Signed-off-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      36da4d86
  21. 19 10月, 2006 3 次提交
  23. 05 10月, 2006 1 次提交
    • D
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      由 David Howells 提交于 
      Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780
  25. 29 9月, 2006 9 次提交
  27. 23 9月, 2006 1 次提交