From: David Laight <David.Laight@ACULAB.COM>
To: 'Linus Torvalds' <torvalds@linux-foundation.org>,
Borislav Petkov <bp@alien8.de>
Cc: David Howells <dhowells@redhat.com>,
kernel test robot <oliver.sang@intel.com>,
"oe-lkp@lists.linux.dev" <oe-lkp@lists.linux.dev>,
"lkp@intel.com" <lkp@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Christian Brauner <brauner@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
Christian Brauner <christian@brauner.io>,
Matthew Wilcox <willy@infradead.org>,
"ying.huang@intel.com" <ying.huang@intel.com>,
"feng.tang@intel.com" <feng.tang@intel.com>,
"fengwei.yin@intel.com" <fengwei.yin@intel.com>
Subject: RE: [linus:master] [iov_iter] c9eec08bac: vm-scalability.throughput -16.9% regression
Date: Thu, 16 Nov 2023 16:58:44 +0000 [thread overview]
Message-ID: <ef760f3b926747598051c848ba85c4a8@AcuMS.aculab.com> (raw)
In-Reply-To: <CAHk-=wjGQh3ucZFmFR0evbKu2OyEuue-bOjsrnCvxSQdj8x6aw@mail.gmail.com>
...
> Of course, it's also possible that with all the function call overhead
> introduced by the CPU mitigations on older CPU's, we should just say
> "rep movsb" is always correct - if you have a new CPU with FSRM it's
> good, and if you have an old CPU it's no worse than the horrendous CPU
> mitigation overhead for function call/returns.
Unless you are stupid enough to use a P4 :-)
I actually doubt anyone cares (esp. for 64bit) about any
cpu that don't optimise long 'rep movsb' (pre sandy bridge).
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-11-16 16:58 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-07 1:40 [linus:master] [iov_iter] c9eec08bac: vm-scalability.throughput -16.9% regression kernel test robot
2023-11-15 12:48 ` David Howells
2023-11-15 13:18 ` David Howells
2023-11-15 15:20 ` David Howells
2023-11-15 16:53 ` Linus Torvalds
2023-11-15 17:38 ` Linus Torvalds
2023-11-15 18:35 ` David Howells
2023-11-15 18:45 ` Linus Torvalds
2023-11-15 19:09 ` Linus Torvalds
2023-11-15 20:54 ` David Howells
2023-11-15 18:38 ` Linus Torvalds
2023-11-15 19:09 ` Borislav Petkov
2023-11-15 19:15 ` Linus Torvalds
2023-11-15 20:07 ` Linus Torvalds
2023-11-16 10:07 ` David Laight
2023-11-16 10:14 ` David Howells
2023-11-16 11:38 ` David Laight
2023-11-15 19:26 ` Linus Torvalds
2023-11-16 15:44 ` Borislav Petkov
2023-11-16 16:44 ` David Howells
2023-11-17 11:35 ` Borislav Petkov
2023-11-17 14:12 ` David Howells
2023-11-17 16:09 ` Borislav Petkov
2023-11-17 16:32 ` Linus Torvalds
2023-11-17 16:44 ` Linus Torvalds
2023-11-17 19:12 ` Borislav Petkov
2023-11-17 21:57 ` Linus Torvalds
2023-11-20 13:32 ` David Howells
2023-11-20 16:06 ` Linus Torvalds
2023-11-20 16:09 ` David Laight
2023-11-16 16:48 ` Linus Torvalds
2023-11-16 16:58 ` David Laight [this message]
2023-11-17 11:44 ` Borislav Petkov
2023-11-17 12:09 ` Jakub Jelinek
2023-11-17 12:18 ` Borislav Petkov
2023-11-17 13:09 ` David Laight
2023-11-17 13:36 ` Linus Torvalds
2023-11-17 15:20 ` David Laight
2023-11-15 21:43 ` David Howells
2023-11-15 21:50 ` Linus Torvalds
2023-11-15 21:59 ` Borislav Petkov
2023-11-15 22:59 ` David Howells
2023-11-16 3:26 ` Linus Torvalds
2023-11-16 16:55 ` David Laight
2023-11-16 17:24 ` Linus Torvalds
2023-11-16 22:53 ` David Laight
2023-11-16 21:09 ` David Howells
2023-11-16 22:36 ` Linus Torvalds
2023-11-20 11:52 ` Borislav Petkov
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