[dpdk-dev] [PATCH v2 0/3] add support for HTM lock elision for x86

Bruce Richardson bruce.richardson at intel.com
Wed Jun 17 15:05:51 CEST 2015


On Tue, Jun 16, 2015 at 10:16:43AM -0700, Roman Dementiev wrote:
> This series of patches adds methods that use hardware memory transactions (HTM)
> on fast-path for DPDK locks (a.k.a. lock elision). Here the methods are
> implemented for x86 using Restricted Transactional Memory instructions (Intel(r)
> Transactional Synchronization Extensions). The implementation fall-backs to
> the normal DPDK lock if HTM is not available or memory transactions fail. This
> is not a replacement for ALL lock usages since not all critical sections
> protected by locks are friendly to HTM. For example, an attempt to perform
> a HW I/O operation inside a hardware memory transaction always aborts
> the transaction since the CPU is not able to roll-back should the transaction
> fail. Therefore, hardware transactional locks are not advised to be used around
> rte_eth_rx_burst() and rte_eth_tx_burst() calls.
> 
> v2 changes
> -added a documentation note about hardware limitations
> 
> Roman Dementiev (3):
>   spinlock: add support for HTM lock elision for x86
>   rwlock: add support for HTM lock elision for x86
>   test scaling of HTM lock elision protecting rte_hash
> 
A change with a conflict in the test makefile was merged last night. However,
the patches themselves otherwise seem ok. 

Thomas, is a V3 needed for this small conflict, or can you handle it on applying
the patch?



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