Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: [linux-usb-devel] Re: [PATCH 00/10] usb-serial: Switches from spin lock to atomic_t. | Date | Tue, 6 Dec 2005 23:48:14 +0100 |
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Am Dienstag, 6. Dezember 2005 21:13 schrieb Eduardo Pereira Habkost: > Anyway, I don't see yet why the atomic_t would make the code slower on > non-smp. Is atomic_add_unless(v, 1, 1) supposed to be slower than > 'if (!v) v = 1;' ?
spin_lock() can be dropped on UP. atomic_XXX must either use an operation on main memory, meaning less efficient code generation, or must disable interrupts even on UP.
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