lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <20200819042438.GF162457@mit.edu> Date: Wed, 19 Aug 2020 00:24:38 -0400 From: "Theodore Y. Ts'o" <tytso@....edu> To: brookxu <brookxu.cn@...il.com> Cc: adilger.kernel@...ger.ca, riteshh@...ux.ibm.com, jack@...e.cz, linux-ext4@...r.kernel.org Subject: Re: [PATCH v5 2/2] ext4: limit the length of per-inode prealloc list On Mon, Aug 17, 2020 at 03:36:15PM +0800, brookxu wrote: > In the scenario of writing sparse files, the per-inode prealloc list may > be very long, resulting in high overhead for ext4_mb_use_preallocated(). > To circumvent this problem, we limit the maximum length of per-inode > prealloc list to 512 and allow users to modify it. > > After patching, we observed that the sys ratio of cpu has dropped, and > the system throughput has increased significantly. We created a process > to write the sparse file, and the running time of the process on the > fixed kernel was significantly reduced, as follows: > > Running time on unfixed kernel: > [root@...CENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat > real 0m2.051s > user 0m0.008s > sys 0m2.026s > > Running time on fixed kernel: > [root@...CENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat > real 0m0.471s > user 0m0.004s > sys 0m0.395s Thanks, applied with Ritesh's suggested spelling fix up. - Ted
Powered by blists - more mailing lists