Re: [dpdk-dev] [dpdk-stable] [PATCH v2 2/4] hash: add local cache for TSX region

["Wang, Yipeng1" <yipeng1.wang@intel.com>]

>-----Original Message-----
>From: Honnappa Nagarahalli [mailto:Honnappa.Nagarahalli@arm.com]
>Sent: Tuesday, November 13, 2018 9:17 AM
>To: Thomas Monjalon <thomas@monjalon.net>; Richardson, Bruce <bruce.richardson@intel.com>; Wang, Yipeng1
><yipeng1.wang@intel.com>
>Cc: stable@dpdk.org; dev@dpdk.org; nd <nd@arm.com>; nd <nd@arm.com>
>Subject: RE: [dpdk-stable] [dpdk-dev] [PATCH v2 2/4] hash: add local cache for TSX region
>> > >  	/* Check extra flags field to check extra options. */
>> > > -	if (params->extra_flag &
>> > > RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT)
>> > > +	if (params->extra_flag &
>> > > RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT) {
>> > > +		use_local_cache = 1;
>> > Do you see the issue even in the case of single writer? Enabling this flag
>> creates local caches on all the data plane cores. This increases the memory
>> usage for the single writer use case. Then there is 'writers on the control
>> plane' use case, the requirement on hash_add rate is comparatively lower
>> when compared to 'writers on the data plane'. The writers also are not pinned
>> to any core as well. In this use case, I am not sure how much having a local
>> cache matters.
>> >
>> > Enabling this flag effectively changes the free slot allocation from a ring to a
>> stack data structure. Does it indicate that for single writer use case with TSX,
>> the free slot (global) data structure should be a stack (rather than a ring)?
>>
>> Is it blocking this patchset from entering in 18.11?
>> If I understand well, there are some fixes for 18.11.

[Wang, Yipeng] Hi Thomas, please go ahead merge the other commits without this one since Honnapa's concern.
I will talk with Honnappa separately on a better way to do this.

Thanks!
>>
>I am fine with the other fixes in this patchset