archive mirror
 help / color / mirror / Atom feed
From: Miklos Szeredi <>
To: Kirill Tkhai <>
Subject: Re: [PATCH 3/3] fuse: Use hash table to link processing request
Date: Tue, 25 Sep 2018 11:08:55 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <153666073461.19117.1958730317836145457.stgit@localhost.localdomain>

On Tue, Sep 11, 2018 at 12:12 PM, Kirill Tkhai <> wrote:
> We noticed the performance bottle neck in FUSE running our
> Virtuozzo storage over rdma. On some types of workload
> we observe 20% of times pent in request_find() in profiler.
> This function is iterating over long requests list, and it
> scales bad.
> The patch introduces hash table to reduce the number
> of iterations, we do in this function. Hash generating
> algorithm is taken from hash_add() function, while
> 512 lines table is used to store pending requests.
> This fixes problem and improves the performance.

Pushed to fuse.git#for-next with a number of small changes.   E.g. I
reduced the number of cachlines to 256 to make the hashtable size just
4k.   Was there a scientific reason for choosing 512 as the optimal
number of cache lines?


  reply	other threads:[~2018-09-25 15:15 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-11 10:11 [PATCH 0/3] fuse: Solve request_find() bottleneck Kirill Tkhai
2018-09-11 10:11 ` [PATCH 1/3] fuse: Change interrupt requests allocation algorhythm Kirill Tkhai
2018-09-11 10:12 ` [PATCH 2/3] fuse: Kill fuse_req::intr_unique Kirill Tkhai
2018-09-11 10:12 ` [PATCH 3/3] fuse: Use hash table to link processing request Kirill Tkhai
2018-09-25  9:08   ` Miklos Szeredi [this message]
2018-09-25  9:35     ` Kirill Tkhai
2018-09-24 12:08 ` [PATCH 0/3] fuse: Solve request_find() bottleneck Kirill Tkhai
2018-09-24 15:04   ` Miklos Szeredi

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='' \ \ \ \ \ \

* 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).