Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread Lionel Cons
On 18 June 2013 10:20, Glenn Fowler g...@research.att.com wrote: you showed ast grep strace output but not gnu grep gnu /usr/bin/grep does read of varying chunk sizes on my redhat linux for NFS files the chunk sizes were around 32Ki I added some test options to the SFIO_OPTIONS env var

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread Glenn Fowler
On Fri, 13 Sep 2013 17:14:03 +0200 Lionel Cons wrote: On 18 June 2013 10:20, Glenn Fowler g...@research.att.com wrote: you showed ast grep strace output but not gnu grep gnu /usr/bin/grep does read of varying chunk sizes on my redhat linux for NFS files the chunk sizes were around 32Ki

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread ольга крыжановская
Glenn, shared mmap() mapping do not have any impact on fork() performance, at least on VM architectures who can share pages (this is common practice since at least SystemV, and no modern Unix or Linux exists which does not do copy-on-write, but more on that below) The pages are not even touched,

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread Glenn Fowler
On Fri, 13 Sep 2013 23:14:22 +0200 =?KOI8-R?B?z8zYx8Egy9LZ1sHOz9fTy8HR?= wrote: Glenn, shared mmap() mapping do not have any impact on fork() performance, at least on VM architectures who can share pages (this is common practice since at least SystemV, and no modern Unix or Linux exists which

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread ольга крыжановская
No, this is not copy on write, this is check-what-to-do-on-access-when-not-mapped. The short explanation is, that the fork() is not the time when an action in the VM system will happen, its the time of the first access to a page, which is not mapped yet, in the current process, when an action will

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread Glenn Fowler
we're getting close again we're not interested in the pages but the metadata for the pages this may be based on incorrect assumptions ... 1Gib mapped and 8Kib page size = 131072 entries for address-to-page lookup at fork() time the parent process has that 131072 entry table in hand what does the

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread Haller, John H (John)
Message- From: ast-users-boun...@lists.research.att.com [mailto:ast-users- boun...@lists.research.att.com] On Behalf Of Glenn Fowler Sent: Friday, September 13, 2013 5:00 PM Subject: Re: [ast-users] Thank you for the grep builtin! we're getting close again we're not interested

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread ольга крыжановская
packet. Regards, John Haller -Original Message- From: ast-users-boun...@lists.research.att.com [mailto:ast-users- boun...@lists.research.att.com] On Behalf Of Glenn Fowler Sent: Friday, September 13, 2013 5:00 PM Subject: Re: [ast-users] Thank you for the grep builtin! we're

Re: [ast-users] Thank you for the grep builtin!

2013-09-13 Thread Haller, John H (John)
packet to the end of the next packet. Regards, John Haller -Original Message- From: ast-users-boun...@lists.research.att.com [mailto:ast-users- boun...@lists.research.att.com] On Behalf Of Glenn Fowler Sent: Friday, September 13, 2013 5:00 PM Subject: Re: [ast-users] Thank

Re: [ast-users] Thank you for the grep builtin!

2013-06-18 Thread Lionel Cons
On 18 June 2013 10:20, Glenn Fowler g...@research.att.com wrote: you showed ast grep strace output but not gnu grep sorry, I didn't verify the data send by my staff gnu /usr/bin/grep does read of varying chunk sizes on my redhat linux for NFS files the chunk sizes were around 32Ki chunk

Re: [ast-users] Thank you for the grep builtin!

2013-06-06 Thread Glenn Fowler
great - any soft numbers on improvement? On Thu, 6 Jun 2013 11:23:27 +0200 Lionel Cons wrote: I'd like say Thank you for adding the grep builtin to ksh93. Today we figured out that this gave a major performance boost and helped a lot working around shoddy or broken grep implementations.