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From: "Wang, Yipeng1" <yipeng1.wang@intel.com>
To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>,
	"Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Gobriel, Sameh" <sameh.gobriel@intel.com>, nd <nd@arm.com>
Subject: Re: [dpdk-dev] [PATCH v4 2/4] hash: add extendable bucket feature
Date: Tue, 2 Oct 2018 23:39:51 +0000	[thread overview]
Message-ID: <D2C4A16CA39F7F4E8E384D204491D7A6614EB03C@FMSMSX151.amr.corp.intel.com> (raw)
In-Reply-To: <AM6PR08MB3672608643961F72B966355098E80@AM6PR08MB3672.eurprd08.prod.outlook.com>

>-----Original Message-----
>From: Honnappa Nagarahalli [mailto:Honnappa.Nagarahalli@arm.com]
>> +
>> +	for (i = RTE_HASH_BUCKET_ENTRIES - 1; i >= 0; i--) {
>> +		if (last_bkt->key_idx[i] != EMPTY_SLOT) {
>> +			cur_bkt->key_idx[pos] = last_bkt->key_idx[i];
>> +			cur_bkt->sig_current[pos] = last_bkt->sig_current[i];
>> +			cur_bkt->sig_alt[pos] = last_bkt->sig_alt[i];
>> +			last_bkt->sig_current[i] = NULL_SIGNATURE;
>> +			last_bkt->sig_alt[i] = NULL_SIGNATURE;
>> +			last_bkt->key_idx[i] = EMPTY_SLOT;
>> +			return;
>In lock-free algorithm, this will require the global counter increment.
>
[Wang, Yipeng] I agree. Similar to your protect for cuckoo displacement, protecting the copy part.
>> +	while (last_bkt->next) {
>> +		prev_bkt = last_bkt;
>> +		last_bkt = last_bkt->next;
>> +	}
>Minor: We are trying to find the last bucket here, along with its previous. May be we can modify 'rte_hash_get_last_bkt' instead?
>
[Wang, Yipeng] Then there will be one more store in each iteration for the regular find_last. I was having an individual function for
this but since it is only used here I removed that. If you think it is necessary or you may reuse it somewhere else for LF, I can add it back.
>> +
>> +	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
>> +		if (last_bkt->key_idx[i] != EMPTY_SLOT)
>> +			break;
>> +	}
>> +	/* found empty bucket and recycle */
>> +	if (i == RTE_HASH_BUCKET_ENTRIES) {
>> +		prev_bkt->next = last_bkt->next = NULL;
>> +		uint32_t index = last_bkt - h->buckets_ext + 1;
>> +		rte_ring_sp_enqueue(h->free_ext_bkts, (void
>> *)(uintptr_t)index);
>In the lock-less algorithm, the bucket cannot be freed immediately. I looked at couple of solutions. The bucket needs to be stored
>internally and should be associated with the key-store index (or position). I am thinking that I will add a field to 'struct rte_hash_key'
>to store the bucket pointer or index.
[Wang, Yipeng] Even if the bucket is recycled immediately, what's the worst could happen? Even if there are readers currently iterating the deleted
Bucket, it is still fine right? It is a miss anyway. 
>
>From the code, my understanding is that we will free only the last bucket. We will never free the middle bucket, please correct me if I
>am wrong. This will keep it simple for the lock-free algorithm.
[Wang, Yipeng] It is correct.
>
>I could work through these issues. So, I do not see any issues for lock-free algorithm (as of now :) ).
>
>> +
>> +	/* Out of bounds of all buckets (both main table and ext table */
>Typo: missing ')'
>
[Wang, Yipeng] Yeah thanks!

  reply	other threads:[~2018-10-02 23:41 UTC|newest]

Thread overview: 107+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-06 17:09 [dpdk-dev] [PATCH v1 0/5] hash: add extendable bucket and partial-key hashing Yipeng Wang
2018-09-06 17:09 ` [dpdk-dev] [PATCH v1 1/5] test: fix bucket size in hash table perf test Yipeng Wang
2018-09-06 17:09 ` [dpdk-dev] [PATCH v1 2/5] test: more accurate hash table perf test output Yipeng Wang
2018-09-06 17:09 ` [dpdk-dev] [PATCH v1 3/5] hash: add extendable bucket feature Yipeng Wang
2018-09-06 17:09 ` [dpdk-dev] [PATCH v1 4/5] test: implement extendable bucket hash test Yipeng Wang
2018-09-06 17:09 ` [dpdk-dev] [PATCH v1 5/5] hash: use partial-key hashing Yipeng Wang
2018-09-21 17:17 ` [dpdk-dev] [PATCH v2 0/7] hash: add extendable bucket and partial key hashing Yipeng Wang
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 1/7] test/hash: fix bucket size in hash perf test Yipeng Wang
2018-09-26 10:04     ` Bruce Richardson
2018-09-27  3:39       ` Wang, Yipeng1
2018-09-27  4:23     ` Honnappa Nagarahalli
2018-09-29  0:31       ` Wang, Yipeng1
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 2/7] test/hash: more accurate hash perf test output Yipeng Wang
2018-09-26 10:07     ` Bruce Richardson
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 3/7] test/hash: fix rw test with non-consecutive cores Yipeng Wang
2018-09-26 11:02     ` Bruce Richardson
2018-09-27  3:40       ` Wang, Yipeng1
2018-09-26 11:13     ` Bruce Richardson
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 4/7] hash: fix unnecessary code Yipeng Wang
2018-09-26 12:55     ` Bruce Richardson
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 5/7] hash: add extendable bucket feature Yipeng Wang
2018-09-27  4:23     ` Honnappa Nagarahalli
2018-09-27 11:15       ` Bruce Richardson
2018-09-27 11:27         ` Ananyev, Konstantin
2018-09-27 12:27           ` Bruce Richardson
2018-09-27 12:33             ` Ananyev, Konstantin
2018-09-27 19:21         ` Honnappa Nagarahalli
2018-09-28 17:35           ` Wang, Yipeng1
2018-09-29 21:09             ` Honnappa Nagarahalli
2018-09-29  1:10       ` Wang, Yipeng1
2018-10-01 20:56         ` Honnappa Nagarahalli
2018-10-02  1:56           ` Wang, Yipeng1
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 6/7] test/hash: implement extendable bucket hash test Yipeng Wang
2018-09-27  4:24     ` Honnappa Nagarahalli
2018-09-29  0:50       ` Wang, Yipeng1
2018-09-21 17:17   ` [dpdk-dev] [PATCH v2 7/7] hash: use partial-key hashing Yipeng Wang
2018-09-27  4:24     ` Honnappa Nagarahalli
2018-09-29  0:55       ` Wang, Yipeng1
2018-09-26 12:57   ` [dpdk-dev] [PATCH v2 0/7] hash: add extendable bucket and partial key hashing Bruce Richardson
2018-09-27  3:41     ` Wang, Yipeng1
2018-09-27  4:23   ` Honnappa Nagarahalli
2018-09-29  0:46     ` Wang, Yipeng1
2018-09-26 12:54 ` [dpdk-dev] [PATCH v3 0/5] hash: fix multiple issues Yipeng Wang
2018-09-26 12:54   ` [dpdk-dev] [PATCH v3 1/5] test/hash: fix bucket size in hash perf test Yipeng Wang
2018-09-27 11:17     ` Bruce Richardson
2018-09-26 12:54   ` [dpdk-dev] [PATCH v3 2/5] test/hash: more accurate hash perf test output Yipeng Wang
2018-09-26 12:54   ` [dpdk-dev] [PATCH v3 3/5] test/hash: fix rw test with non-consecutive cores Yipeng Wang
2018-09-27 11:18     ` Bruce Richardson
2018-09-26 12:54   ` [dpdk-dev] [PATCH v3 4/5] test/hash: fix missing file in meson build file Yipeng Wang
2018-09-27 11:22     ` Bruce Richardson
2018-09-26 12:54   ` [dpdk-dev] [PATCH v3 5/5] hash: fix unused define Yipeng Wang
2018-09-28 14:11   ` [dpdk-dev] [PATCH v4 0/5] hash: fix multiple issues Yipeng Wang
2018-09-28 14:11     ` [dpdk-dev] [PATCH v4 1/5] test/hash: fix bucket size in hash perf test Yipeng Wang
2018-10-01 20:28       ` Honnappa Nagarahalli
2018-09-28 14:11     ` [dpdk-dev] [PATCH v4 2/5] test/hash: more accurate hash perf test output Yipeng Wang
2018-09-28 14:11     ` [dpdk-dev] [PATCH v4 3/5] test/hash: fix rw test with non-consecutive cores Yipeng Wang
2018-09-28 14:11     ` [dpdk-dev] [PATCH v4 4/5] test/hash: fix missing file in meson build file Yipeng Wang
2018-09-28 14:11     ` [dpdk-dev] [PATCH v4 5/5] hash: fix unused define Yipeng Wang
2018-10-25 22:04     ` [dpdk-dev] [PATCH v4 0/5] hash: fix multiple issues Thomas Monjalon
2018-09-26 20:26 ` [dpdk-dev] [PATCH v3 0/3] hash: add extendable bucket and partial key hashing Yipeng Wang
2018-09-26 20:26   ` [dpdk-dev] [PATCH v3 1/3] hash: add extendable bucket feature Yipeng Wang
2018-09-26 20:26   ` [dpdk-dev] [PATCH v3 2/3] test/hash: implement extendable bucket hash test Yipeng Wang
2018-09-26 20:26   ` [dpdk-dev] [PATCH v3 3/3] hash: use partial-key hashing Yipeng Wang
2018-09-28 17:23   ` [dpdk-dev] [PATCH v4 0/4] hash: add extendable bucket and partial key hashing Yipeng Wang
2018-09-28 17:23     ` [dpdk-dev] [PATCH v4 1/4] hash: fix race condition in iterate Yipeng Wang
2018-10-01 20:23       ` Honnappa Nagarahalli
2018-10-02  0:17         ` Wang, Yipeng1
2018-10-02  4:26           ` Honnappa Nagarahalli
2018-10-02 23:53             ` Wang, Yipeng1
2018-09-28 17:23     ` [dpdk-dev] [PATCH v4 2/4] hash: add extendable bucket feature Yipeng Wang
2018-10-02  3:58       ` Honnappa Nagarahalli
2018-10-02 23:39         ` Wang, Yipeng1 [this message]
2018-10-03  4:37           ` Honnappa Nagarahalli
2018-10-03 15:08           ` Stephen Hemminger
2018-10-03 15:08       ` Stephen Hemminger
2018-10-03 16:53         ` Wang, Yipeng1
2018-10-03 17:59           ` Honnappa Nagarahalli
2018-10-04  1:22             ` Wang, Yipeng1
2018-09-28 17:23     ` [dpdk-dev] [PATCH v4 3/4] test/hash: implement extendable bucket hash test Yipeng Wang
2018-10-01 19:53       ` Honnappa Nagarahalli
2018-09-28 17:23     ` [dpdk-dev] [PATCH v4 4/4] hash: use partial-key hashing Yipeng Wang
2018-10-01 20:09       ` Honnappa Nagarahalli
2018-10-03 19:05     ` [dpdk-dev] [PATCH v4 0/4] hash: add extendable bucket and partial key hashing Dharmik Thakkar
2018-10-01 18:34   ` [dpdk-dev] [PATCH v5 " Yipeng Wang
2018-10-01 18:34     ` [dpdk-dev] [PATCH v5 1/4] hash: fix race condition in iterate Yipeng Wang
2018-10-02 17:26       ` Honnappa Nagarahalli
2018-10-01 18:35     ` [dpdk-dev] [PATCH v5 2/4] hash: add extendable bucket feature Yipeng Wang
2018-10-01 18:35     ` [dpdk-dev] [PATCH v5 3/4] test/hash: implement extendable bucket hash test Yipeng Wang
2018-10-01 18:35     ` [dpdk-dev] [PATCH v5 4/4] hash: use partial-key hashing Yipeng Wang
2018-10-02 20:52       ` Dharmik Thakkar
2018-10-03  0:43         ` Wang, Yipeng1
2018-10-03 19:10     ` [dpdk-dev] [PATCH v5 0/4] hash: add extendable bucket and partial key hashing Dharmik Thakkar
2018-10-04  0:36       ` Wang, Yipeng1
2018-10-04 16:35   ` [dpdk-dev] [PATCH v6 " Yipeng Wang
2018-10-04 16:35     ` [dpdk-dev] [PATCH v6 1/4] hash: fix race condition in iterate Yipeng Wang
2018-10-04 16:35     ` [dpdk-dev] [PATCH v6 2/4] hash: add extendable bucket feature Yipeng Wang
2018-10-04 16:35     ` [dpdk-dev] [PATCH v6 3/4] test/hash: implement extendable bucket hash test Yipeng Wang
2018-10-04 16:35     ` [dpdk-dev] [PATCH v6 4/4] hash: use partial-key hashing Yipeng Wang
2018-10-10 21:27     ` [dpdk-dev] [PATCH v7 0/4] hash: add extendable bucket and partial key hashing Yipeng Wang
2018-10-10 21:27       ` [dpdk-dev] [PATCH v7 1/4] hash: fix race condition in iterate Yipeng Wang
2018-10-10 21:27       ` [dpdk-dev] [PATCH v7 2/4] hash: add extendable bucket feature Yipeng Wang
2018-10-10 21:27       ` [dpdk-dev] [PATCH v7 3/4] test/hash: implement extendable bucket hash test Yipeng Wang
2018-10-10 21:27       ` [dpdk-dev] [PATCH v7 4/4] hash: use partial-key hashing Yipeng Wang
2018-10-16 18:47       ` [dpdk-dev] [PATCH] doc: update release note for hash library Yipeng Wang
2018-10-17 20:09         ` Honnappa Nagarahalli
2018-10-25 18:45           ` Wang, Yipeng1
2018-10-25 23:07             ` Thomas Monjalon

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