Messages in this thread | | | Date | Fri, 17 Sep 2004 00:21:27 -0700 | From | Tony Lee <> | Subject | Re: [patch] remove the BKL (Big Kernel Lock), this time for real |
| |
On Fri, 17 Sep 2004 08:43:21 +0200, Ingo Molnar <mingo@elte.hu> wrote: > > * Bill Huey <bhuey@lnxw.com> wrote: > > > Judging from how the Linux code is done and the numbers I get from > > Bill Irwin in casual conversation, the Linux SMP approach is clearly > > the right track at this time with it's hand honed per-CPU awareness of > > things. The only serious problem that spinlocks have as they aren't > > preemptable, which is what Ingo is trying to fix. > > a clarification: note that the current BKL is a special case. No way do > i suggest that the BKS is the proper model for any SMP implementation. > It is a narrow special-case because it wraps historic UP-only kernel > code. > > our primary multiprocessing primitives are still the following 4: > lockless data structures, RCU, spinlocks and mutexes. (reverse ordered > by level of parallelism.) The BKS is basically a fifth method, a special > type of semaphore that i'd never want to be seen used by any new SMP > code. It is completely local to sched.c. > > Ingo
I coded a IPC system before use atomic add + share memory. It works very well (fast) on 4 CPU SMP system, since it doesn't use any locking API at all. Very good for resource allocation for SMP. I implemented speciall malloc/free use by ISR, different prority process completely without any lock. Negative side, it use more memory.
-- -Tony Having a lot of fun with Xilinx Virtex Pro II reconfigurable HW + ppc + Linux - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |