Phil On 11/4/16 4:14 PM, Phil Blundell wrote: > On Fri, 2016-11-04 at 11:22 -0700, Khem Raj wrote: >> >> >> On 11/4/16 2:07 AM, Li Zhou wrote: >>> >>> The swpb in macro MUTEX_SET will cause "undefined instruction" >>> error >>> on the new arm arches which don't support this assembly instruction >>> any more. If use ldrex/strex to replace swpb, the old arm arches >>> don't >>> support them. So to avoid this issue, just disable the ARM >>> assembler >>> mutex code, and use the default pthreads mutex. >>> > >> it would be good to keep this for older < armv5 arches > > I guess you meant "<= ARMv5". STREX etc were introduced in ARMv6, so > ARMv5 (and ARMv5TE) don't have it. But in any case, won't the default > libpthread mutex work just fine on those older architectures? There is > no SMP on anything before ARMv6 anyway so lock contention will be > relatively low, and it seems fairly unlikely that anybody has a real- > world application which uses db so heavily that the mutex > implementation will have any noticeable performance impact.
yes I meant <= v5, it should work usually, I am just thinking its a untested option, it may not be as bad as I think but some testing might be useful > > And, given that it's now something like 15 years since support for > STREX was introduced in ARMv6, and more than 10 years since support for > SWP was deleted in ARMv7, it doesn't seem entirely unreasonable for oe- > core to pick the newer paradigm as the case to optimise for. Distros > that want to target ARMv5 or older are obviously free to do so and they > can carry the SWP patch locally if they want to. But as far as oe-core > itself is concerned, at this point it seems like it's just scar tissue. yeah agree here. > > p. > -- _______________________________________________ Openembedded-core mailing list [email protected] http://lists.openembedded.org/mailman/listinfo/openembedded-core
