BPF Archive on lore.kernel.org
 help / color / Atom feed
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Andrii Nakryiko <andriin@fb.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
	daniel@iogearbox.net, andrii.nakryiko@gmail.com,
	kernel-team@fb.com, "Paul E . McKenney" <paulmck@kernel.org>,
	Jonathan Lemon <jonathan.lemon@gmail.com>
Subject: Re: [PATCH v2 bpf-next 6/7] bpf: add BPF ringbuf and perf buffer benchmarks
Date: Thu, 21 May 2020 18:21:47 -0700
Message-ID: <20200522012147.shnwybm5my7dgy4v@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200517195727.279322-7-andriin@fb.com>

On Sun, May 17, 2020 at 12:57:26PM -0700, Andrii Nakryiko wrote:
> +
> +static inline int roundup_len(__u32 len)
> +{
> +	/* clear out top 2 bits */
> +	len <<= 2;
> +	len >>= 2;
> +	/* add length prefix */
> +	len += RINGBUF_META_LEN;
> +	/* round up to 8 byte alignment */
> +	return (len + 7) / 8 * 8;
> +}

the same round_up again?

> +
> +static void ringbuf_custom_process_ring(struct ringbuf_custom *r)
> +{
> +	unsigned long cons_pos, prod_pos;
> +	int *len_ptr, len;
> +	bool got_new_data;
> +
> +	cons_pos = smp_load_acquire(r->consumer_pos);
> +	while (true) {
> +		got_new_data = false;
> +		prod_pos = smp_load_acquire(r->producer_pos);
> +		while (cons_pos < prod_pos) {
> +			len_ptr = r->data + (cons_pos & r->mask);
> +			len = smp_load_acquire(len_ptr);
> +
> +			/* sample not committed yet, bail out for now */
> +			if (len & RINGBUF_BUSY_BIT)
> +				return;
> +
> +			got_new_data = true;
> +			cons_pos += roundup_len(len);
> +
> +			atomic_inc(&buf_hits.value);
> +		}
> +		if (got_new_data)
> +			smp_store_release(r->consumer_pos, cons_pos);
> +		else
> +			break;
> +	};
> +}

copy paste from libbpf? why?

  reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-17 19:57 [PATCH v2 bpf-next 0/7] BPF ring buffer Andrii Nakryiko
2020-05-17 19:57 ` [PATCH v2 bpf-next 1/7] bpf: implement BPF ring buffer and verifier support for it Andrii Nakryiko
2020-05-19 12:57   ` kbuild test robot
2020-05-19 23:53   ` kbuild test robot
2020-05-22  0:25   ` Paul E. McKenney
2020-05-22 18:46     ` Andrii Nakryiko
2020-05-25 16:01       ` Paul E. McKenney
2020-05-25 18:45         ` Andrii Nakryiko
2020-05-22  1:07   ` Alexei Starovoitov
2020-05-22 18:48     ` Andrii Nakryiko
2020-05-25 20:34     ` Andrii Nakryiko
2020-05-17 19:57 ` [PATCH v2 bpf-next 2/7] tools/memory-model: add BPF ringbuf MPSC litmus tests Andrii Nakryiko
2020-05-22  0:34   ` Paul E. McKenney
2020-05-22 18:51     ` Andrii Nakryiko
2020-05-25 23:33       ` Andrii Nakryiko
2020-05-26  3:05         ` Paul E. McKenney
2020-05-17 19:57 ` [PATCH v2 bpf-next 3/7] bpf: track reference type in verifier Andrii Nakryiko
2020-05-22  1:13   ` Alexei Starovoitov
2020-05-22 18:53     ` Andrii Nakryiko
2020-05-17 19:57 ` [PATCH v2 bpf-next 4/7] libbpf: add BPF ring buffer support Andrii Nakryiko
2020-05-22  1:15   ` Alexei Starovoitov
2020-05-22 18:56     ` Andrii Nakryiko
2020-05-17 19:57 ` [PATCH v2 bpf-next 5/7] selftests/bpf: add BPF ringbuf selftests Andrii Nakryiko
2020-05-22  1:20   ` Alexei Starovoitov
2020-05-22 18:58     ` Andrii Nakryiko
2020-05-17 19:57 ` [PATCH v2 bpf-next 6/7] bpf: add BPF ringbuf and perf buffer benchmarks Andrii Nakryiko
2020-05-22  1:21   ` Alexei Starovoitov [this message]
2020-05-22 19:07     ` Andrii Nakryiko
2020-05-17 19:57 ` [PATCH v2 bpf-next 7/7] docs/bpf: add BPF ring buffer design notes Andrii Nakryiko
2020-05-22  1:23   ` Alexei Starovoitov
2020-05-22 19:08     ` Andrii Nakryiko
2020-05-25  9:59   ` Alban Crequy
2020-05-25 19:12     ` Andrii Nakryiko

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=20200522012147.shnwybm5my7dgy4v@ast-mbp.dhcp.thefacebook.com \
    --to=alexei.starovoitov@gmail.com \
    --cc=andrii.nakryiko@gmail.com \
    --cc=andriin@fb.com \
    --cc=ast@fb.com \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=jonathan.lemon@gmail.com \
    --cc=kernel-team@fb.com \
    --cc=netdev@vger.kernel.org \
    --cc=paulmck@kernel.org \
    /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

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git