From: Hao Xu <[email protected]>
To: Christian Brauner <[email protected]>
Cc: [email protected], Jens Axboe <[email protected]>,
Dominique Martinet <[email protected]>,
Pavel Begunkov <[email protected]>,
Alexander Viro <[email protected]>,
Stefan Roesch <[email protected]>, Clay Harris <[email protected]>,
Dave Chinner <[email protected]>,
[email protected], Wanpeng Li <[email protected]>
Subject: Re: [PATCH 3/3] io_uring: add support for getdents
Date: Sun, 16 Jul 2023 19:57:26 +0800 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <20230713-verglast-pfuschen-50197f8be98b@brauner>
On 7/13/23 23:14, Christian Brauner wrote:
> Could someone with perf experience try and remove that f_count == 1
> optimization from __fdget_pos() completely and make it always acquire
> the mutex? I wonder what the performance impact of that is.
Hi Christian,
For your reference, I did a simple test: writed a c program that open a
directory which has 1000 empty files, then call sync getdents64 on it
repeatedly until we get all the entries. I run this program 10 times for
"with f_count==1
optimization" and "always do the lock" version.
Got below data:
with f_count==1:
time cost: 0.000379
time cost: 0.000116
time cost: 0.000090
time cost: 0.000101
time cost: 0.000095
time cost: 0.000092
time cost: 0.000092
time cost: 0.000095
time cost: 0.000092
time cost: 0.000121
time cost: 0.000092
time cost avg: 0.00009859999999999998
always do the lock:
time cost: 0.000095
time cost: 0.000099
time cost: 0.000123
time cost: 0.000124
time cost: 0.000092
time cost: 0.000099
time cost: 0.000092
time cost: 0.000092
time cost: 0.000093
time cost: 0.000094
time cost avg: 0.00010029999999999997
So about 1.724% increment
[1] the first run is not showed here since that try does real IO
and diff a lot.
[2] the time cost calculation is by gettimeofday()
[3] run it in a VM which has 2 CPUs and 1GB memory.
Regards,
Hao
next prev parent reply other threads:[~2023-07-16 11:57 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-11 11:40 [PATCH v3 0/3] io_uring getdents Hao Xu
2023-07-11 11:40 ` [PATCH 1/3] fs: split off vfs_getdents function of getdents64 syscall Hao Xu
2023-07-11 13:02 ` Ammar Faizi
2023-07-12 8:03 ` Hao Xu
2023-07-12 13:55 ` Ammar Faizi
2023-07-13 4:17 ` Hao Xu
2023-07-11 23:41 ` Dave Chinner
2023-07-11 23:50 ` Jens Axboe
2023-07-12 11:14 ` Christian Brauner
2023-07-11 11:40 ` [PATCH 2/3] vfs_getdents/struct dir_context: add flags field Hao Xu
2023-07-12 11:31 ` Christian Brauner
2023-07-12 16:02 ` Dominique Martinet
2023-07-13 4:12 ` Hao Xu
2023-07-11 11:40 ` [PATCH 3/3] io_uring: add support for getdents Hao Xu
2023-07-11 12:15 ` Dominique Martinet
2023-07-12 7:53 ` Hao Xu
2023-07-12 16:10 ` Dominique Martinet
2023-07-13 4:05 ` Hao Xu
2023-07-13 4:40 ` Hao Xu
2023-07-13 4:50 ` Dominique Martinet
2023-07-12 8:01 ` Hao Xu
2023-07-12 15:27 ` Christian Brauner
2023-07-13 4:35 ` Hao Xu
2023-07-13 7:10 ` Christian Brauner
2023-07-13 9:06 ` Hao Xu
2023-07-13 15:14 ` Christian Brauner
2023-07-16 11:57 ` Hao Xu [this message]
2023-07-18 6:55 ` Hao Xu
2023-07-11 23:47 ` [PATCH v3 0/3] io_uring getdents Dave Chinner
2023-07-11 23:51 ` Jens Axboe
2023-07-12 0:53 ` Dominique Martinet
2023-07-12 0:56 ` Jens Axboe
2023-07-12 3:16 ` Hao Xu
2023-07-12 3:12 ` Hao Xu
2023-07-12 3:19 ` Hao Xu
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