From: "Mattias Rönnblom" <hofors@lysator.liu.se>
To: "Mattias Rönnblom" <mattias.ronnblom@ericsson.com>, dev@dpdk.org
Cc: "Heng Wang" <heng.wang@ericsson.com>,
"Stephen Hemminger" <stephen@networkplumber.org>,
"Tyler Retzlaff" <roretzla@linux.microsoft.com>,
"Morten Brørup" <mb@smartsharesystems.com>
Subject: Re: [RFC v6 5/6] eal: add atomic bit operations
Date: Fri, 3 May 2024 08:41:09 +0200 [thread overview]
Message-ID: <1e703819-d3b2-4127-95c2-33d32d535432@lysator.liu.se> (raw)
In-Reply-To: <20240502055706.112443-6-mattias.ronnblom@ericsson.com>
On 2024-05-02 07:57, Mattias Rönnblom wrote:
> Add atomic bit test/set/clear/assign/flip and
> test-and-set/clear/assign/flip functions.
>
> All atomic bit functions allow (and indeed, require) the caller to
> specify a memory order.
>
> RFC v6:
> * Have rte_bit_atomic_test() accept const-marked bitsets.
>
> RFC v4:
> * Add atomic bit flip.
> * Mark macro-generated private functions experimental.
>
> RFC v3:
> * Work around lack of C++ support for _Generic (Tyler Retzlaff).
>
> RFC v2:
> o Add rte_bit_atomic_test_and_assign() (for consistency).
> o Fix bugs in rte_bit_atomic_test_and_[set|clear]().
> o Use <rte_stdatomics.h> to support MSVC.
>
> Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
> Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> ---
> lib/eal/include/rte_bitops.h | 428 +++++++++++++++++++++++++++++++++++
> 1 file changed, 428 insertions(+)
>
> diff --git a/lib/eal/include/rte_bitops.h b/lib/eal/include/rte_bitops.h
> index caec4f36bb..9cde982113 100644
> --- a/lib/eal/include/rte_bitops.h
> +++ b/lib/eal/include/rte_bitops.h
> @@ -21,6 +21,7 @@
>
> #include <rte_compat.h>
> #include <rte_debug.h>
> +#include <rte_stdatomic.h>
>
> #ifdef __cplusplus
> extern "C" {
> @@ -399,6 +400,202 @@ extern "C" {
> uint32_t *: __rte_bit_once_flip32, \
> uint64_t *: __rte_bit_once_flip64)(addr, nr)
>
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Test if a particular bit in a word is set with a particular memory
> + * order.
> + *
> + * Test a bit with the resulting memory load ordered as per the
> + * specified memory order.
> + *
> + * @param addr
> + * A pointer to the word to query.
> + * @param nr
> + * The index of the bit.
> + * @param memory_order
> + * The memory order to use. See <rte_stdatomics.h> for details.
> + * @return
> + * Returns true if the bit is set, and false otherwise.
> + */
> +#define rte_bit_atomic_test(addr, nr, memory_order) \
> + _Generic((addr), \
> + uint32_t *: __rte_bit_atomic_test32, \
> + const uint32_t *: __rte_bit_atomic_test32, \
> + uint64_t *: __rte_bit_atomic_test64, \
> + const uint64_t *: __rte_bit_atomic_test64)(addr, nr, \
> + memory_order)
Should __rte_bit_atomic_test32()'s addr parameter be marked volatile,
and two volatile-marked branches added to the above list? Both the
C11-style GCC built-ins and the C11-proper atomic functions have
addresses marked volatile. The Linux kernel and the old __sync GCC
built-ins on the other hand, doesn't (although I think you still get
volatile semantics). The only point of "volatile", as far as I can see,
is to avoid warnings in case the user passed a volatile-marked pointer.
The drawback is that *you're asking for volatile semantics*, although
with the current compilers, it seems like that is what you get,
regardless if you asked for it or not.
Just to be clear: even these functions would accept volatile-marked
pointers, non-volatile pointers should be accepted as well (and should
generally be preferred).
Isn't parallel programming in C lovely.
<snip>
next prev parent reply other threads:[~2024-05-03 6:41 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-02 13:53 [RFC 0/7] Improve EAL bit operations API Mattias Rönnblom
2024-03-02 13:53 ` [RFC 1/7] eal: extend bit manipulation functions Mattias Rönnblom
2024-03-02 17:05 ` Stephen Hemminger
2024-03-03 6:26 ` Mattias Rönnblom
2024-03-04 16:34 ` Tyler Retzlaff
2024-03-05 18:01 ` Mattias Rönnblom
2024-03-05 18:06 ` Tyler Retzlaff
2024-04-25 8:58 ` [RFC v2 0/6] Improve EAL bit operations API Mattias Rönnblom
2024-04-25 8:58 ` [RFC v2 1/6] eal: extend bit manipulation functionality Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 0/6] Improve EAL bit operations API Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 1/6] eal: extend bit manipulation functionality Mattias Rönnblom
2024-04-29 11:12 ` Morten Brørup
2024-04-30 9:55 ` [RFC v4 0/6] Improve EAL bit operations API Mattias Rönnblom
2024-04-30 9:55 ` [RFC v4 1/6] eal: extend bit manipulation functionality Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 0/6] Improve EAL bit operations API Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 1/6] eal: extend bit manipulation functionality Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 0/6] Improve EAL bit operations API Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 1/6] eal: extend bit manipulation functionality Mattias Rönnblom
2024-05-05 8:37 ` [RFC v7 0/6] Improve EAL bit operations API Mattias Rönnblom
2024-05-05 8:37 ` [RFC v7 1/6] eal: extend bit manipulation functionality Mattias Rönnblom
2024-05-05 8:37 ` [RFC v7 2/6] eal: add unit tests for bit operations Mattias Rönnblom
2024-05-05 8:37 ` [RFC v7 3/6] eal: add exactly-once bit access functions Mattias Rönnblom
2024-05-07 19:17 ` Morten Brørup
2024-05-08 6:47 ` Mattias Rönnblom
2024-05-08 7:33 ` Morten Brørup
2024-05-08 8:00 ` Mattias Rönnblom
2024-05-08 8:11 ` Morten Brørup
2024-05-08 9:27 ` Mattias Rönnblom
2024-05-08 10:08 ` Morten Brørup
2024-05-08 15:15 ` Stephen Hemminger
2024-05-08 16:16 ` Morten Brørup
2024-05-05 8:37 ` [RFC v7 4/6] eal: add unit tests for " Mattias Rönnblom
2024-05-05 8:37 ` [RFC v7 5/6] eal: add atomic bit operations Mattias Rönnblom
2024-05-05 8:37 ` [RFC v7 6/6] eal: add unit tests for atomic bit access functions Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 2/6] eal: add unit tests for bit operations Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 3/6] eal: add exactly-once bit access functions Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 4/6] eal: add unit tests for " Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 5/6] eal: add atomic bit operations Mattias Rönnblom
2024-05-03 6:41 ` Mattias Rönnblom [this message]
2024-05-03 23:30 ` Tyler Retzlaff
2024-05-04 15:36 ` Mattias Rönnblom
2024-05-02 5:57 ` [RFC v6 6/6] eal: add unit tests for atomic bit access functions Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 2/6] eal: add unit tests for bit operations Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 3/6] eal: add exactly-once bit access functions Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 4/6] eal: add unit tests for " Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 5/6] eal: add atomic bit operations Mattias Rönnblom
2024-04-30 12:08 ` [RFC v5 6/6] eal: add unit tests for atomic bit access functions Mattias Rönnblom
2024-04-30 9:55 ` [RFC v4 2/6] eal: add unit tests for bit operations Mattias Rönnblom
2024-04-30 9:55 ` [RFC v4 3/6] eal: add exactly-once bit access functions Mattias Rönnblom
2024-04-30 9:55 ` [RFC v4 4/6] eal: add unit tests for " Mattias Rönnblom
2024-04-30 10:37 ` Morten Brørup
2024-04-30 11:58 ` Mattias Rönnblom
2024-04-30 9:55 ` [RFC v4 5/6] eal: add atomic bit operations Mattias Rönnblom
2024-04-30 9:55 ` [RFC v4 6/6] eal: add unit tests for atomic bit access functions Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 2/6] eal: add unit tests for bit operations Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 3/6] eal: add exactly-once bit access functions Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 4/6] eal: add unit tests for " Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 5/6] eal: add atomic bit operations Mattias Rönnblom
2024-04-29 9:51 ` [RFC v3 6/6] eal: add unit tests for atomic bit access functions Mattias Rönnblom
2024-04-25 8:58 ` [RFC v2 2/6] eal: add unit tests for bit operations Mattias Rönnblom
2024-04-25 8:58 ` [RFC v2 3/6] eal: add exactly-once bit access functions Mattias Rönnblom
2024-04-25 8:58 ` [RFC v2 4/6] eal: add unit tests for " Mattias Rönnblom
2024-04-25 8:58 ` [RFC v2 5/6] eal: add atomic bit operations Mattias Rönnblom
2024-04-25 10:25 ` Morten Brørup
2024-04-25 14:36 ` Mattias Rönnblom
2024-04-25 16:18 ` Morten Brørup
2024-04-26 9:39 ` Mattias Rönnblom
2024-04-26 12:00 ` Morten Brørup
2024-04-28 15:37 ` Mattias Rönnblom
2024-04-29 7:24 ` Morten Brørup
2024-04-30 16:52 ` Tyler Retzlaff
2024-04-25 8:58 ` [RFC v2 6/6] eal: add unit tests for atomic bit access functions Mattias Rönnblom
2024-04-25 18:05 ` [RFC v2 0/6] Improve EAL bit operations API Tyler Retzlaff
2024-04-26 11:17 ` Mattias Rönnblom
2024-04-26 21:35 ` Patrick Robb
2024-03-02 13:53 ` [RFC 2/7] eal: add generic bit manipulation macros Mattias Rönnblom
2024-03-04 8:16 ` Heng Wang
2024-03-04 15:41 ` Mattias Rönnblom
2024-03-04 16:42 ` Tyler Retzlaff
2024-03-05 18:08 ` Mattias Rönnblom
2024-03-05 18:22 ` Tyler Retzlaff
2024-03-05 20:02 ` Mattias Rönnblom
2024-03-05 20:53 ` Tyler Retzlaff
2024-03-02 13:53 ` [RFC 3/7] eal: add bit manipulation functions which read or write once Mattias Rönnblom
2024-03-02 13:53 ` [RFC 4/7] eal: add generic once-type bit operations macros Mattias Rönnblom
2024-03-02 13:53 ` [RFC 5/7] eal: add atomic bit operations Mattias Rönnblom
2024-03-02 13:53 ` [RFC 6/7] eal: add generic " Mattias Rönnblom
2024-03-02 13:53 ` [RFC 7/7] eal: deprecate relaxed family of " Mattias Rönnblom
2024-03-02 17:07 ` Stephen Hemminger
2024-03-03 6:30 ` Mattias Rönnblom
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