Re: Spinlocks, yet again: analysis and proposed patches

Tom Lane wrote:

> I attach two proposed patches: the first removes the cmpb/jne from
> the x86 TAS assembly code, and the second one does the s_lock changes
> enumerated as points #2, #3, #4. The first one in particular needs
> more testing to see if it hurts performance on any non-Opteron x86
> chips. (If so, we'd just make it conditional to x86_64.)
>

2x PIII 1G 2G Freebsd 6.0Beta4

8.1beta1 (2005-08-28):

N runtime: 1 85s 2 139s 4 220s

8.1beta1 (2005-08-28) + patch 1 (s_lock.h only)

N runtime: 1 89s 2 137s 4 229s

8.1beta1 (2005-08-28) + patch 2

N runtime: 1 84s 2 108s 4 214s

Observe the interesting little speed improvement for patch 2 with 2
processes (seems to be repeatable).

Let me know if you want to see vmstat output for any of these.

regards

Mark