patches for DPDK stable branches
 help / color / mirror / Atom feed
From: "Ma, WenwuX" <wenwux.ma@intel.com>
To: fengchengwen <fengchengwen@huawei.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "Jiale, SongX" <songx.jiale@intel.com>,
	"stable@dpdk.org" <stable@dpdk.org>
Subject: RE: [PATCH v2] dmadev: fix structure alignment
Date: Fri, 15 Mar 2024 06:25:49 +0000	[thread overview]
Message-ID: <MN0PR11MB6110987DEBDCF7D341C39863EB282@MN0PR11MB6110.namprd11.prod.outlook.com> (raw)
In-Reply-To: <096d2161-026c-f89e-c44b-340a3148bccc@huawei.com>

Hi Chengwen,

> -----Original Message-----
> From: fengchengwen <fengchengwen@huawei.com>
> Sent: Friday, March 15, 2024 2:06 PM
> To: Ma, WenwuX <wenwux.ma@intel.com>; dev@dpdk.org
> Cc: Jiale, SongX <songx.jiale@intel.com>; stable@dpdk.org
> Subject: Re: [PATCH v2] dmadev: fix structure alignment
> 
> Hi Wenwu,
> 
> On 2024/3/15 9:43, Wenwu Ma wrote:
> > The structure rte_dma_dev needs only 8 byte alignment.
> > This patch replaces __rte_cache_aligned of rte_dma_dev with
> > __rte_aligned(8).
> >
> > Fixes: b36970f2e13e ("dmadev: introduce DMA device library")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> > ---
> > v2:
> >  - Because of performance drop, adjust the code to
> >    no longer demand cache line alignment
> 
> Which two versions observed performance drop? And which benchmark
> observed drop?
> Could you provide more information?
> 
> >
V1 patch:
https://patches.dpdk.org/project/dpdk/patch/20240308053711.1260154-1-wenwux.ma@intel.com/

To view detailed results, visit:
https://lab.dpdk.org/results/dashboard/patchsets/29472/

> > ---
> >  lib/dmadev/rte_dmadev_pmd.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/dmadev/rte_dmadev_pmd.h
> b/lib/dmadev/rte_dmadev_pmd.h
> > index 58729088ff..b569bb3502 100644
> > --- a/lib/dmadev/rte_dmadev_pmd.h
> > +++ b/lib/dmadev/rte_dmadev_pmd.h
> > @@ -122,7 +122,7 @@ enum rte_dma_dev_state {
> >   * @internal
> >   * The generic data structure associated with each DMA device.
> >   */
> > -struct __rte_cache_aligned rte_dma_dev {
> > +struct __rte_aligned(8) rte_dma_dev {
> 
> The DMA fast-path was implemented by struct rte_dma_fp_objs, which is not
> rte_dma_dev? So why is it a problem here?
> 
> Thanks
> 
The DMA device object is expected to align cache line, so clang will use “vmovaps” assembly instruction, 

And the instruction demands 16 bytes alignment or will cause segment fault in some environments.


> >  	/** Device info which supplied during device initialization. */
> >  	struct rte_device *device;
> >  	struct rte_dma_dev_data *data; /**< Pointer to shared device data.
> > */
> >

  reply	other threads:[~2024-03-15  6:25 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-08  5:37 [PATCH] " Wenwu Ma
2024-03-08  7:01 ` fengchengwen
2024-03-15  1:43 ` [PATCH v2] " Wenwu Ma
2024-03-15  6:02   ` Tyler Retzlaff
2024-03-15  6:06   ` fengchengwen
2024-03-15  6:25     ` Ma, WenwuX [this message]
2024-03-15  7:44       ` Ma, WenwuX
2024-03-15  8:31         ` fengchengwen
2024-03-15  9:27           ` Ma, WenwuX
2024-03-20  4:11             ` fengchengwen
2024-03-20  7:34               ` Ma, WenwuX
2024-03-19  9:48   ` Jiale, SongX
2024-03-20  7:23 ` [PATCH v3] " Wenwu Ma
2024-03-20  9:31   ` fengchengwen
2024-06-27 12:46     ` Thomas Monjalon
2024-03-20 11:37   ` Thomas Monjalon
2024-03-21  1:25     ` Ma, WenwuX
2024-03-21  8:30       ` Thomas Monjalon
2024-03-21  8:57         ` Ma, WenwuX
2024-03-21  9:18         ` Ma, WenwuX
2024-03-21 10:06           ` Thomas Monjalon
2024-03-21 16:05             ` Tyler Retzlaff

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=MN0PR11MB6110987DEBDCF7D341C39863EB282@MN0PR11MB6110.namprd11.prod.outlook.com \
    --to=wenwux.ma@intel.com \
    --cc=dev@dpdk.org \
    --cc=fengchengwen@huawei.com \
    --cc=songx.jiale@intel.com \
    --cc=stable@dpdk.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
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).