Linux-RDMA Archive on lore.kernel.org
 help / color / Atom feed
From: Jinpu Wang <jinpu.wang@ionos.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Gioh Kim <gi-oh.kim@ionos.com>,
	linux-rdma@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Haris Iqbal <haris.iqbal@ionos.com>,
	Gioh Kim <gi-oh.kim@cloud.ionos.com>
Subject: Re: [PATCHv2 for-next 1/3] RDMA/rtrs-clt: Print more info when an error happens
Date: Mon, 12 Apr 2021 14:53:55 +0200
Message-ID: <CAMGffEn8AYhtO8WF4sWjPu2uVgZDL4aRiT+sPjqtK6VaGsk3bQ@mail.gmail.com> (raw)
In-Reply-To: <YHQ/7MTKGD/UO4pW@unreal>

On Mon, Apr 12, 2021 at 2:41 PM Leon Romanovsky <leon@kernel.org> wrote:
>
> On Mon, Apr 12, 2021 at 02:22:51PM +0200, Jinpu Wang wrote:
> > On Tue, Apr 6, 2021 at 2:41 PM Leon Romanovsky <leon@kernel.org> wrote:
> > >
> > > On Tue, Apr 06, 2021 at 02:36:37PM +0200, Gioh Kim wrote:
> > > > From: Gioh Kim <gi-oh.kim@cloud.ionos.com>
> > > >
> > > > Client prints only error value and it is not enough for debugging.
> > > >
> > > > 1. When client receives an error from server:
> > > > the client does not only print the error value but also
> > > > more information of server connection.
> > > >
> > > > 2. When client failes to send IO:
> > > > the client gets an error from RDMA layer. It also
> > > > print more information of server connection.
> > > >
> > > > Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
> > > > Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
> > > > ---
> > > >  drivers/infiniband/ulp/rtrs/rtrs-clt.c | 33 ++++++++++++++++++++++----
> > > >  1 file changed, 29 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> > > > index 5062328ac577..a534b2b09e13 100644
> > > > --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> > > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> > > > @@ -437,6 +437,11 @@ static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
> > > >       req->in_use = false;
> > > >       req->con = NULL;
> > > >
> > > > +     if (unlikely(errno)) {
> > >
> > > I'm sorry, but all your patches are full of these likely/unlikely cargo
> > > cult. Can you please provide supportive performance data or delete all
> > > likely/unlikely in all rtrs code?
> >
> > Hi Leon,
> >
> > All the likely/unlikely from the non-fast path was removed as you
> > suggested in the past.
> > This one is on IO path, my understanding is for the fast path, with
> > likely/unlikely macro,
> > the compiler will optimize the code for better branch prediction.
>
> In theory yes, in practice. gcc 10 generated same assembly code when I
> placed likely() and replaced it with unlikely() later.
That's a surprise to me.

Just checked, min gcc requirement is 4.9[1],  debian Buster is using
gcc 8.3, upcoming Bullseye will use gcc 10.2

[1]: https://www.kernel.org/doc/html/latest/process/changes.html
>
> >
> > We will run some benchmarks to see if it makes a difference.
> >
> > Thanks
> > >
> > > Thanks

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 12:36 [PATCHv2 for-next 0/3] Improve debugging messages Gioh Kim
2021-04-06 12:36 ` [PATCHv2 for-next 1/3] RDMA/rtrs-clt: Print more info when an error happens Gioh Kim
2021-04-06 12:41   ` Leon Romanovsky
2021-04-09  9:57     ` Gioh Kim
2021-04-12 12:22     ` Jinpu Wang
2021-04-12 12:41       ` Leon Romanovsky
2021-04-12 12:53         ` Jinpu Wang [this message]
2021-04-12 14:00           ` Gioh Kim
2021-04-12 17:34             ` Leon Romanovsky
2021-04-13  5:31               ` Haakon Bugge
2021-04-13  6:43                 ` Leon Romanovsky
2021-04-13 13:11                   ` Gioh Kim
2021-04-13 19:31                     ` Leon Romanovsky
2021-04-13 22:52   ` Jason Gunthorpe
2021-04-06 12:36 ` [PATCHv2 for-next 2/3] RDMA/rtrs-srv: More debugging info when fail to send reply Gioh Kim
2021-04-06 12:36 ` [PATCHv2 for-next 3/3] RDMA/rtrs-clt: Simplify error message Gioh Kim
2021-04-13 22:52 ` [PATCHv2 for-next 0/3] Improve debugging messages Jason Gunthorpe

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=CAMGffEn8AYhtO8WF4sWjPu2uVgZDL4aRiT+sPjqtK6VaGsk3bQ@mail.gmail.com \
    --to=jinpu.wang@ionos.com \
    --cc=bvanassche@acm.org \
    --cc=dledford@redhat.com \
    --cc=gi-oh.kim@cloud.ionos.com \
    --cc=gi-oh.kim@ionos.com \
    --cc=haris.iqbal@ionos.com \
    --cc=jgg@ziepe.ca \
    --cc=leon@kernel.org \
    --cc=linux-rdma@vger.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

Linux-RDMA Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rdma/0 linux-rdma/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 linux-rdma linux-rdma/ https://lore.kernel.org/linux-rdma \
		linux-rdma@vger.kernel.org
	public-inbox-index linux-rdma

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rdma


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