Re: [linux-usb-devel] Re: [PATCH 00/10] usb-serial: Switches fromspin lock to atomic_t.

[Luiz Fernando Capitulino]

On Wed, 07 Dec 2005 13:34:38 +0100
Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

| On Wed, 2005-12-07 at 10:30 -0200, Luiz Fernando Capitulino wrote:
| > On Wed, 07 Dec 2005 13:27:13 +0100
| > Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
| > 
| > | 
| > | >  Isn't it right? Is the URB write so fast that switching to atomic_t
| > | > doesn't pay-off?
| > | 
| > | an atomic_t access and a spinlock are basically the same price... so
| > | what's the payoff ?
| > 
| >  One lock less,
| 
| where? 

 In the 'usb_serial_port', my patch number nine removes the spin lock.

| spin_unlock in principle runs unlocked on x86 at least
| (except for ppro workarounds but those are/should be optional)
| 
| 


-- 
Luiz Fernando N. Capitulino
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