From: Feifei Wang <Feifei.Wang2@arm.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Ruifeng Wang <Ruifeng.Wang@arm.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>, nd <nd@arm.com>, nd <nd@arm.com>,
nd <nd@arm.com>
Subject: [dpdk-dev] 回复: [RFC PATCH v3 1/5] eal: add new definitions for wait scheme
Date: Thu, 14 Oct 2021 03:08:09 +0000 [thread overview]
Message-ID: <DB9PR08MB69238C710EA067653EDC5A30C8B89@DB9PR08MB6923.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <DM6PR11MB4491424E1DBA460026B5FD729AB79@DM6PR11MB4491.namprd11.prod.outlook.com>
> -----邮件原件-----
> 发件人: Ananyev, Konstantin <konstantin.ananyev@intel.com>
> 发送时间: Wednesday, October 13, 2021 11:04 PM
> 收件人: Feifei Wang <Feifei.Wang2@arm.com>; Ruifeng Wang
> <Ruifeng.Wang@arm.com>
> 抄送: dev@dpdk.org; nd <nd@arm.com>; nd <nd@arm.com>
> 主题: RE: [dpdk-dev] [RFC PATCH v3 1/5] eal: add new definitions for wait
> scheme
>
> >
> > [snip]
> >
> > > > diff --git a/lib/eal/include/generic/rte_pause.h
> > > > b/lib/eal/include/generic/rte_pause.h
> > > > index 668ee4a184..4e32107eca 100644
> > > > --- a/lib/eal/include/generic/rte_pause.h
> > > > +++ b/lib/eal/include/generic/rte_pause.h
> > > > @@ -111,6 +111,84 @@ rte_wait_until_equal_64(volatile uint64_t
> > > > *addr,
> > > uint64_t expected,
> > > > while (__atomic_load_n(addr, memorder) != expected)
> > > > rte_pause();
> > > > }
> > > > +
> > > > +/*
> > > > + * Wait until a 16-bit *addr breaks the condition, with a relaxed
> > > > +memory
> > > > + * ordering model meaning the loads around this API can be reordered.
> > > > + *
> > > > + * @param addr
> > > > + * A pointer to the memory location.
> > > > + * @param mask
> > > > + * A mask of value bits in interest
> > > > + * @param expected
> > > > + * A 16-bit expected value to be in the memory location.
> > > > + * @param cond
> > > > + * A symbol representing the condition (==, !=).
> > > > + * @param memorder
> > > > + * Two different memory orders that can be specified:
> > > > + * __ATOMIC_ACQUIRE and __ATOMIC_RELAXED. These map to
> > > > + * C++11 memory orders with the same names, see the C++11
> > > > +standard or
> > > > + * the GCC wiki on atomic synchronization for detailed definition.
> > > > + */
> > >
> > > Hmm, so now we have 2 APIs doing similar thing:
> > > rte_wait_until_equal_n() and rte_wait_event_n().
> > > Can we probably unite them somehow?
> > > At least make rte_wait_until_equal_n() to use rte_wait_event_n()
> underneath.
> > >
> > You are right. We plan to change rte_wait_until_equal API after this
> > new scheme is achieved. And then, we will merge wait_unil into
> > wait_event definition in the next new patch series.
> >
> > > > +#define rte_wait_event_16(addr, mask, expected, cond, memorder)
> > > \
> > > > +do {
> \
> > > > + assert(memorder == __ATOMIC_ACQUIRE || memorder ==
> > > > +__ATOMIC_RELAXED); \
> > >
> > > And why user is not allowed to use __ATOMIC_SEQ_CST here?
> > Actually this is just a load operation, and acquire here is enough to
> > make sure 'load addr value' can be before other operations.
> >
> > > BTW, if we expect memorder to always be a constant, might be better
> > > BUILD_BUG_ON()?
> > If I understand correctly, you means we can replace 'assert' by
> 'build_bug_on':
> > RTE_BUILD_BUG_ON(memorder != __ATOMIC_ACQUIRE && memorder
> > !=__ATOMIC_RELAXED);
>
> Yes, that was my thought.
> In that case I think we should be able to catch wrong memorder at compilation
> stage.
>
> >
> > >
> > > > + \
> > > > + while ((__atomic_load_n(addr, memorder) & mask) cond expected)
> > > \
> > > > + rte_pause(); \
> > > > +} while (0)
> > >
> > > Two thoughts with these macros:
> > > 1. It is a goof practise to put () around macro parameters in the macro
> body.
> > > Will save from a lot of unexpected troubles.
> > > 2. I think these 3 macros can be united into one.
> > > Something like:
> > >
> > > #define rte_wait_event(addr, mask, expected, cond, memorder) do {\
> > > typeof (*(addr)) val = __atomic_load_n((addr), (memorder)); \
> > > if ((val & (typeof(val))(mask)) cond (typeof(val))(expected)) \
> > > break; \
> > > rte_pause(); \
> > > } while (1);
> > For this point, I think it is due to different size need to use
> > different assembly instructions in arm architecture. For example, load
> > 16 bits instruction is "ldxrh %w[tmp], [%x[addr]"
> > load 32 bits instruction is " ldxr %w[tmp], [%x[addr]"
> > load 64 bits instruction is " ldxr %x[tmp], [%x[addr] "
>
> Ok, but it could be then something like that for arm specific code:
> if (sizeof(val) == sizeof(uint16_t)) \
> __LOAD_EXC_16(...); \
> else if (sizeof(val) == sizeof(uint32_t)) \
> __LOAD_EXC_32(...); \
> else if (sizeof(val) == sizeof(uint64_t)) \
> __LOAD_EXC_64(...); \
> ...
>
I thinks we should use "addr" as judgement:
rte_wait_event(addr, mask, expected, cond, memorder)
if (sizeof(*addr)) == sizeof(uint16_t)
uint16_t value \
assert(memorder == __ATOMIC_ACQUIRE || memorder == __ATOMIC_RELAXED); \
__LOAD_EXC_16(addr, value, memorder) \
if ((value & mask) cond expected) { \
__SEVL() \
do { \
__WFE() \
__LOAD_EXC_16(addr, value, memorder) \
} while ((value & mask) cond expected); \
}
if (sizeof(*addr)) == sizeof(uint32_t)
..........
if (sizeof(*addr)) == sizeof(uint64_t)
...........
> > And for consistency, we also use 3 APIs in generic path.
> Honestly, even one multi-line macro doesn't look nice.
> Having 3 identical ones looks even worse.
next prev parent reply other threads:[~2021-10-14 3:08 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 5:32 [dpdk-dev] [RFC PATCH v1 0/5] add new API for wait until scheme Feifei Wang
2021-09-02 5:32 ` [dpdk-dev] [RFC PATCH v1 1/5] eal: " Feifei Wang
2021-09-02 5:32 ` [dpdk-dev] [RFC PATCH v1 2/5] eal: use wait until scheme for read pflock Feifei Wang
2021-09-02 5:32 ` [dpdk-dev] [RFC PATCH v1 3/5] eal: use wait until scheme for mcslock Feifei Wang
2021-09-02 5:32 ` [dpdk-dev] [RFC PATCH v1 4/5] lib/bpf: use wait until scheme for Rx/Tx iteration Feifei Wang
2021-09-02 5:32 ` [dpdk-dev] [RFC PATCH v1 5/5] lib/distributor: use wait until scheme Feifei Wang
2021-09-02 15:22 ` [dpdk-dev] [RFC PATCH v1 0/5] add new API for " Stephen Hemminger
2021-09-03 7:02 ` [dpdk-dev] 回复: " Feifei Wang
2021-09-23 9:58 ` [dpdk-dev] [RFC PATCH v2 0/5] add new definitions for wait scheme Feifei Wang
2021-09-23 9:58 ` [dpdk-dev] [RFC PATCH v2 1/5] eal: " Feifei Wang
2021-09-23 9:58 ` [dpdk-dev] [RFC PATCH v2 2/5] eal: use wait event for read pflock Feifei Wang
2021-09-23 9:59 ` [dpdk-dev] [RFC PATCH v2 3/5] eal: use wait event scheme for mcslock Feifei Wang
2021-09-23 9:59 ` [dpdk-dev] [RFC PATCH v2 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration Feifei Wang
2021-09-24 18:07 ` Ananyev, Konstantin
2021-09-26 2:19 ` [dpdk-dev] 回复: " Feifei Wang
2021-09-23 9:59 ` [dpdk-dev] [RFC PATCH v2 5/5] lib/distributor: use wait event scheme Feifei Wang
2021-09-26 6:32 ` [dpdk-dev] [RFC PATCH v3 0/5] add new definitions for wait scheme Feifei Wang
2021-09-26 6:32 ` [dpdk-dev] [RFC PATCH v3 1/5] eal: " Feifei Wang
2021-10-07 16:18 ` Ananyev, Konstantin
2021-10-12 8:09 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-13 15:03 ` [dpdk-dev] " Ananyev, Konstantin
2021-10-13 17:00 ` Stephen Hemminger
2021-10-14 3:14 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-14 3:08 ` Feifei Wang [this message]
2021-09-26 6:32 ` [dpdk-dev] [RFC PATCH v3 2/5] eal: use wait event for read pflock Feifei Wang
2021-09-26 6:33 ` [dpdk-dev] [RFC PATCH v3 3/5] eal: use wait event scheme for mcslock Feifei Wang
2021-09-26 6:33 ` [dpdk-dev] [RFC PATCH v3 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration Feifei Wang
2021-10-07 15:50 ` Ananyev, Konstantin
2021-10-07 17:40 ` Ananyev, Konstantin
2021-10-20 6:20 ` [dpdk-dev] 回复: " Feifei Wang
2021-09-26 6:33 ` [dpdk-dev] [RFC PATCH v3 5/5] lib/distributor: use wait event scheme Feifei Wang
2021-10-20 8:45 ` [dpdk-dev] [PATCH v4 0/5] add new definitions for wait scheme Feifei Wang
2021-10-20 8:45 ` [dpdk-dev] [PATCH v4 1/5] eal: " Feifei Wang
2021-10-21 16:24 ` Ananyev, Konstantin
2021-10-25 9:20 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-25 14:28 ` [dpdk-dev] " Ananyev, Konstantin
2021-10-26 1:08 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-22 0:10 ` [dpdk-dev] " Jerin Jacob
2021-10-25 9:30 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-25 9:43 ` [dpdk-dev] " Jerin Jacob
2021-10-26 1:11 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-20 8:45 ` [dpdk-dev] [PATCH v4 2/5] eal: use wait event for read pflock Feifei Wang
2021-10-20 8:45 ` [dpdk-dev] [PATCH v4 3/5] eal: use wait event scheme for mcslock Feifei Wang
2021-10-20 8:45 ` [dpdk-dev] [PATCH v4 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration Feifei Wang
2021-10-20 8:45 ` [dpdk-dev] [PATCH v4 5/5] lib/distributor: use wait event scheme Feifei Wang
2021-10-26 8:01 ` [dpdk-dev] [PATCH v5 0/5] add new definitions for wait scheme Feifei Wang
2021-10-26 8:02 ` [dpdk-dev] [PATCH v5 1/5] eal: " Feifei Wang
2021-10-26 8:08 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-26 9:46 ` [dpdk-dev] " Ananyev, Konstantin
2021-10-26 9:59 ` Ananyev, Konstantin
2021-10-27 6:56 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-26 8:02 ` [dpdk-dev] [PATCH v5 2/5] eal: use wait event for read pflock Feifei Wang
2021-10-26 8:02 ` [dpdk-dev] [PATCH v5 3/5] eal: use wait event scheme for mcslock Feifei Wang
2021-10-26 8:02 ` [dpdk-dev] [PATCH v5 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration Feifei Wang
2021-10-26 8:18 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-26 9:43 ` [dpdk-dev] " Ananyev, Konstantin
2021-10-26 12:56 ` Ananyev, Konstantin
2021-10-27 7:04 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-27 7:31 ` Feifei Wang
2021-10-27 14:47 ` [dpdk-dev] " Ananyev, Konstantin
2021-10-28 6:24 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-26 8:02 ` [dpdk-dev] [PATCH v5 5/5] lib/distributor: use wait event scheme Feifei Wang
2021-10-27 8:10 ` [dpdk-dev] [PATCH v6 0/4] add new definitions for wait scheme Feifei Wang
2021-10-27 8:10 ` [dpdk-dev] [PATCH v6 1/4] eal: " Feifei Wang
2021-10-27 8:10 ` [dpdk-dev] [PATCH v6 2/4] eal: use wait event for read pflock Feifei Wang
2021-10-27 8:10 ` [dpdk-dev] [PATCH v6 3/4] eal: use wait event scheme for mcslock Feifei Wang
2021-10-27 11:16 ` Mattias Rönnblom
2021-10-28 6:32 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-27 8:10 ` [dpdk-dev] [PATCH v6 4/4] lib/distributor: use wait event scheme Feifei Wang
2021-10-27 10:57 ` [dpdk-dev] [PATCH v6 0/4] add new definitions for wait scheme Jerin Jacob
2021-10-28 6:33 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-28 6:56 ` [dpdk-dev] [PATCH v7 0/5] " Feifei Wang
2021-10-28 6:56 ` [dpdk-dev] [PATCH v7 1/5] eal: " Feifei Wang
2021-10-28 7:15 ` Jerin Jacob
2021-10-28 7:40 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-28 7:51 ` [dpdk-dev] " Jerin Jacob
2021-10-28 9:27 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-28 13:14 ` [dpdk-dev] " Ananyev, Konstantin
2021-10-28 6:56 ` [dpdk-dev] [PATCH v7 2/5] eal: use wait event for read pflock Feifei Wang
2021-10-28 6:56 ` [dpdk-dev] [PATCH v7 3/5] eal: use wait event scheme for mcslock Feifei Wang
2021-10-28 7:02 ` Jerin Jacob
2021-10-28 7:14 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-28 6:56 ` [dpdk-dev] [PATCH v7 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration Feifei Wang
2021-10-28 13:15 ` Ananyev, Konstantin
2021-10-28 6:56 ` [dpdk-dev] [PATCH v7 5/5] lib/distributor: use wait event scheme Feifei Wang
2021-10-29 8:20 ` [dpdk-dev] [PATCH v8 0/5] add new definitions for wait scheme Feifei Wang
2021-10-29 8:20 ` [dpdk-dev] [PATCH v8 1/5] eal: " Feifei Wang
2021-10-29 13:54 ` Jerin Jacob
2021-10-31 8:38 ` David Marchand
2021-11-01 2:29 ` [dpdk-dev] 回复: " Feifei Wang
2021-10-29 8:20 ` [dpdk-dev] [PATCH v8 2/5] eal: use wait event for read pflock Feifei Wang
2021-10-29 13:55 ` Jerin Jacob
2021-10-31 8:37 ` David Marchand
2021-10-29 8:20 ` [dpdk-dev] [PATCH v8 3/5] eal: use wait event scheme for mcslock Feifei Wang
2021-10-29 13:55 ` Jerin Jacob
2021-10-31 8:37 ` David Marchand
2021-10-29 8:20 ` [dpdk-dev] [PATCH v8 4/5] lib/bpf: use wait event scheme for Rx/Tx iteration Feifei Wang
2021-10-31 8:37 ` David Marchand
2021-10-29 8:20 ` [dpdk-dev] [PATCH v8 5/5] lib/distributor: use wait event scheme Feifei Wang
2021-10-29 13:58 ` Jerin Jacob
2021-10-31 8:38 ` David Marchand
2021-11-01 12:44 ` David Hunt
2021-11-01 6:00 ` [dpdk-dev] [PATCH v9 0/5] add new helper for wait scheme Feifei Wang
2021-11-01 6:00 ` [dpdk-dev] [PATCH v9 1/5] eal: add a new generic " Feifei Wang
2021-11-01 6:00 ` [dpdk-dev] [PATCH v9 2/5] pflock: use wait until scheme for read pflock Feifei Wang
2021-11-03 14:46 ` David Marchand
2021-11-04 1:24 ` [dpdk-dev] 回复: " Feifei Wang
2021-11-01 6:00 ` [dpdk-dev] [PATCH v9 3/5] mcslock: use wait until scheme for mcslock Feifei Wang
2021-11-01 6:00 ` [dpdk-dev] [PATCH v9 4/5] bpf: use wait until scheme for Rx/Tx iteration Feifei Wang
2021-11-01 6:00 ` [dpdk-dev] [PATCH v9 5/5] distributor: use wait until scheme Feifei Wang
2021-11-01 16:05 ` Pattan, Reshma
2021-11-02 2:00 ` [dpdk-dev] 回复: " Feifei Wang
2021-11-03 14:55 ` [dpdk-dev] [PATCH v9 0/5] add new helper for wait scheme David Marchand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=DB9PR08MB69238C710EA067653EDC5A30C8B89@DB9PR08MB6923.eurprd08.prod.outlook.com \
--to=feifei.wang2@arm.com \
--cc=Ruifeng.Wang@arm.com \
--cc=dev@dpdk.org \
--cc=konstantin.ananyev@intel.com \
--cc=nd@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).