From: "De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
To: "Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>, "edreddy@gmail.com" <edreddy@gmail.com>
Subject: Re: [dpdk-dev] [PATCH] hash: fix to support multi process
Date: Fri, 25 Mar 2016 15:08:24 +0000 [thread overview]
Message-ID: <E115CCD9D858EF4F90C690B0DCB4D8973C8D0B57@IRSMSX108.ger.corp.intel.com> (raw)
In-Reply-To: <20160325144104.GB7916@bricha3-MOBL3>
Hi,
> -----Original Message-----
> From: Richardson, Bruce
> Sent: Friday, March 25, 2016 2:41 PM
> To: De Lara Guarch, Pablo
> Cc: dev@dpdk.org; edreddy@gmail.com
> Subject: Re: [PATCH] hash: fix to support multi process
>
> On Thu, Mar 24, 2016 at 01:56:44PM +0000, Pablo de Lara wrote:
> > Hash library used a function pointer to choose a different
> > key compare function, depending on the key size.
> > As a result, multiple processes could not use the same hash table,
> > as the function addresses vary from one process to another.
> >
> > Instead, a jump table is used, so each process has its own
> > function addresses, accessing this table with an index stored
> > in the hash table (note that using a custom key compare function
> > is not supported in multi-process mode).
> >
> > Fixes: 48a399119619 ("hash: replace with cuckoo hash implementation")
> >
> > Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
>
> This is a hard problem to solve, but this probably looks the least-worst
> solution
> to it. Pablo, I assume the performance hit for lookups is pretty small here?
Yes, performance degradation is negligible.
>
> One small nit in the code below, and a comment on the doc change.
Will send a v2 with the changes. Anyway, I was waiting for Djama and Zhang
to give some feedback here and see if it works for them.
Thanks,
Pablo
> Otherwise,
>
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
>
> > ---
> > doc/guides/rel_notes/release_16_04.rst | 5 ++
> > lib/librte_hash/rte_cuckoo_hash.c | 85 ++++++++++++++++++++++++++-
> -------
> > 2 files changed, 71 insertions(+), 19 deletions(-)
> >
> > diff --git a/doc/guides/rel_notes/release_16_04.rst
> b/doc/guides/rel_notes/release_16_04.rst
> > index 2785b29..c4359dd 100644
> > --- a/doc/guides/rel_notes/release_16_04.rst
> > +++ b/doc/guides/rel_notes/release_16_04.rst
> > @@ -351,6 +351,11 @@ Libraries
> > Fix crc32c hash functions to return a valid crc32c value for data lengths
> > not multiple of 4 bytes.
> >
> > +* **hash: Fixed hash library to support multi-process mode.**
> > +
> > + Fix hash library to support multi-process mode, using a jump table,
> > + instead of storing a function pointer to the key compare function.
> > +
> You probably need to clarify here and in the other docs (e.g. API doc) that:
> * multi-process mode only works with the built-in functions and key sizes.
> * a custom function not in the jump table can be used but only in single-
> process
> mode.
>
> > * **librte_port: Fixed segmentation fault for ring and ethdev writer
> nodrop.**
> >
> > Fixed core dump issue on txq and swq when dropless is set to yes.
> > diff --git a/lib/librte_hash/rte_cuckoo_hash.c
> b/lib/librte_hash/rte_cuckoo_hash.c
> > index 71b5b76..38c19ab 100644
> > --- a/lib/librte_hash/rte_cuckoo_hash.c
> > +++ b/lib/librte_hash/rte_cuckoo_hash.c
> > @@ -102,6 +102,41 @@ EAL_REGISTER_TAILQ(rte_hash_tailq)
> >
> > #define LCORE_CACHE_SIZE 8
> >
> > +/*
> > + * All different options to select a key compare function,
> > + * based on the key size and custom function.
> > + */
> > +enum cmp_jump_table_case {
> > + KEY_CUSTOM = 0,
> > + KEY_16_BYTES,
> > + KEY_32_BYTES,
> > + KEY_48_BYTES,
> > + KEY_64_BYTES,
> > + KEY_80_BYTES,
> > + KEY_96_BYTES,
> > + KEY_112_BYTES,
> > + KEY_128_BYTES,
> > + KEY_OTHER_BYTES,
> > + NUM_KEY_CMP_CASES,
> > +};
> > +
> > +/*
> > + * Table storing all different key compare functions
> > + * (multi-process supported)
> > + */
> > +rte_hash_cmp_eq_t cmp_jump_table[NUM_KEY_CMP_CASES] = {
> > + NULL,
> > + rte_hash_k16_cmp_eq,
> > + rte_hash_k32_cmp_eq,
> > + rte_hash_k48_cmp_eq,
> > + rte_hash_k64_cmp_eq,
> > + rte_hash_k80_cmp_eq,
> > + rte_hash_k96_cmp_eq,
> > + rte_hash_k112_cmp_eq,
> > + rte_hash_k128_cmp_eq,
> > + memcmp
> > +};
>
> Array should be const.
>
> /Bruce
next prev parent reply other threads:[~2016-03-25 15:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 13:56 Pablo de Lara
2016-03-25 14:41 ` Bruce Richardson
2016-03-25 15:08 ` De Lara Guarch, Pablo [this message]
2016-03-30 17:34 ` [dpdk-dev] [PATCH v2] " Pablo de Lara
2016-04-01 13:07 ` Thomas Monjalon
2016-04-01 14:08 ` De Lara Guarch, Pablo
2016-04-01 15:03 ` [dpdk-dev] [PATCH v3 0/2] Multi-process support in hash library Pablo de Lara
2016-04-01 15:03 ` [dpdk-dev] [PATCH v3 1/2] hash: use RTE_ARCH_X86 macro for X86 systems Pablo de Lara
2016-04-01 15:03 ` [dpdk-dev] [PATCH v3 2/2] hash: fix to support multi process Pablo de Lara
2016-04-01 16:57 ` [dpdk-dev] [PATCH v3 0/2] Multi-process support in hash library Thomas Monjalon
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