October 2004 - Darwin-dev - lists.apple.com

Re: Mac OS X version at compile-time
by Finlay Dobbie 06 Oct '04

06 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On 6 Oct 2004, at 23:23, Peter Lovell wrote: -- Finlay _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Does anyone know of a convenient way to determine at compile-time (C preprocessor time, actually) which version of headers are being used? I know there are macros in "AvailabilityMacros.h" but that's not applicable to the problem I have. ... In early versions, there is not typedef for "socklen_t". ... So, is there a #define somewhere which I can test?? Or a more appropriate solution? Generally it's considered better practice to test for exactly the functionliaty that you require. Does your project have a configure script? If so, you could make that check of socklen_t is defined, and conditionally typedef it if needs be. This email sent to site_archiver(a)lists.apple.com

1 0

Mac OS X version at compile-time
by Peter Lovell 06 Oct '04

06 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com /* * Data types. */ typedef u_char sa_family_t; #ifdef _BSD_SOCKLEN_T_ typedef _BSD_SOCKLEN_T_ socklen_t; #undef _BSD_SOCKLEN_T_ #endif Thanks.....Peter _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Does anyone know of a convenient way to determine at compile-time (C preprocessor time, actually) which version of headers are being used? I know there are macros in "AvailabilityMacros.h" but that's not applicable to the problem I have. I'm trying to adapt an open-source project for Max OS X. This will then be built by various developers as needed, on varying OSs and versions. Most of this is OK but I ran into a problem with a change to <sys/socket.h> In early versions, there is not typedef for "socklen_t". But in OS X 10.2 and later, there is this definition ... So, my code which includes <sys/socket.h> cannot determine whether it is defined or not. I think an easy solution for this would have been to add #define SOCKLEN_T_DEFINED in the block, but that opportunity has passed us by. The only way I can see is to check the version of the headers being used. So, is there a #define somewhere which I can test?? Or a more appropriate solution? This email sent to site_archiver(a)lists.apple.com

1 0

Re: mmap modified data not to be swapped out but saved?
by Jim Magee 06 Oct '04

06 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Oct 2, 2004, at 2:58 PM, Dylan McNamee wrote: --Jim _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Ben Dougall asked: with mmap once you've read in some of a file and made some modifications is there anyway to avoid those modifications being swapped out to the backing store? what would be preferable is in the event of the system needing more memory, rather than swapping out those modifications, save them directly to the original file -- is that what happens now, by default maybe, or is there anyway of doing that? While I haven't examined Darwin's code lately, I am pretty familiar with the Mach's VM code from years past, and my memory says that what you want to have happen is supported. (At pageout, "dirty" pages are written back to the file backing the mapped region, which is a file-backed Memory Object). Revisiting the mmap man page reminds me that this might only be the case if the region is mmapped including the MAP_SHARED flag. You're memory (and reading of the manpage) are correct. Using MAP_SHARED read/write, modifications to mapped files get written back to the original file. Using MAP_PRIVATE results in a private copy-on-write mapping of the file where local modifications get written to swap instead. This email sent to site_archiver(a)lists.apple.com

1 0

Re: Serial port question
by Kenny Millar 05 Oct '04

05 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Serial port question
by Godfrey van der Linden 05 Oct '04

05 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

1 0

Serial port question
by Kenny Millar 05 Oct '04

05 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Directory Services API
by Finlay Dobbie 04 Oct '04

04 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On 4 Oct 2004, at 21:28, Mr. Wong wrote: -- Finlay _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Does anyone here have any experience using the Directory Services API... I tried playing with it a bit and it seems archaic at best.....if anyone knows any good resources please point them in my direction :)... thanks! Have you looked at the documentation and the SDK? <http://developer.apple.com/documentation/Networking/Conceptual/ Open_Directory/index.html> <http://developer.apple.com/sdk/#DirectorySvcs> This email sent to site_archiver(a)lists.apple.com

1 0

Directory Services API
by Mr. Wong 04 Oct '04

04 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hello list, --Matthew. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Does anyone here have any experience using the Directory Services API... I tried playing with it a bit and it seems archaic at best.....if anyone knows any good resources please point them in my direction :)... thanks! This email sent to site_archiver(a)lists.apple.com

1 0

re: fread + journaling = slow? [not journaling]
by Paul Carnine 04 Oct '04

04 Oct '04

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com User-agent: Microsoft-Entourage/10.1.1.2418 Folk: I spoke too soon. In fresh light this morning the issue is not related to Journaling. I am not sure this is the right list any more, because the problem has to do with using the Finder to do a file-copy or duplicate on a file with a resource fork. But in the end, it's an fread()/semaphore-in-kernel issue... Let me know (privately) where you think I should post this (and sorry for the bandwidth here). My test file is a 2meg file with a small resource fork. My test code (posted before) just randomly reads 4096 blocks from the input file. My tests: (I used DiskUtility to do the mounting/unmounting) Here's the new issue: > time ./tst /Volumes/Larry/file 4.4s So, my test is slow now. > umount /Volumes/Larry (using disk utility) > mount /Volumes/Larry (using disk utility) > time ./tst /Volumes/Larry/file1 0.4s Just unmount, then mount and wham - back up to speed. Now it gets interesting: Use "Finder" to do a file copy to file2: > time ./tst /Volumes/Larry/file2 4.4s Woah, slow again?! Now it gets really fun, use "ditto --rsrc" to copy > ditto --rsrc /Volumes/Larry/file2 /Volumes/Larry/file3 > time ./tst /Volumes/Larry/file3 0.4s Back up to speed! The terminal "cp" cmd also "removes" the speed block: > cp /Volumes/Larry/file2 /Volumes/Larry/file4 > time ./tst /Volumes/Larry/file4 0.4s And just to be sure I'm not smoking crack, here's the original file, still slow: > time ./tst /Volumes/Larry/file2 4.4s Why does the copied file have different performance than an uncopied file? But only when copied with the finder? Now I can go on -- if I do the same test with a file that *has no resource fork*, then the "Finder copy" leaves the file just as fast. FWIW, Finder-Duplicate does the same thing. So it seems to be Finder + RsrcFork = slow access on resulting file. If you unmount/remount the Volume, then speed is back to "normal". This is on 10.3.5, volume Larry has journaling off. It feels to me like the Finder isn't releasing the resource fork and that's causing some sort of semaphore to kick in (when my test is "slow" all time is spent in the kernel on semaphores). "lsof" doesn't show the file being open, but perhaps "lsof" doesn't show resource forks... Any ideas what's going on or, more importantly, how I can get around this? I just want fread() to have good performance... -pdc _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

1 0

fread + journaling = slow?
by Paul Carnine 04 Oct '04

04 Oct '04

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Microsoft-Entourage/10.1.1.2418 Folk: To make a *very* long story as short as I can, I am running into a performance issue that has me scratching my head a little bit (and might save somebody else some time in the future when list searching reappears). The issue: when journaling is on, I see poor fread() performance. Shark: all time is spent in semaphores in the kernel. poor == 10x slower. The code in question (see below) creates the following output: *** Moe:~/proj/journal pdc$ time ./tj /{pathcut}/test.data file size: 1984 kb (1.9375 meg) total reads: 2031616 real 0m4.880s user 0m0.120s sys 0m1.130s *** Do nothing else but this, using Disk Utility: Turn Journaling Off on data file volume. Unmount Volume. Mount Volume. *** Moe:~/proj/journal pdc$ time ./tj /{pathcut}test.data file size: 1984 kb (1.9375 meg) total reads: 2031616 real 0m0.413s user 0m0.070s sys 0m0.240s *** 4.9s vs 0.4s And this extra 4.4s is not a constant time -- it's at least linear. So, what gives? Is this normal behaviour? Any Ideas? Yes, I have re-implemented my app to use mmap(), but issues I've run into with that are forcing me to re-evaluate the original issue: slow fread() when Journaling is on. Thanks for any ideas and sorry so verbose, -pdc --- snip --- /* compiled with "cc -o jt jt.c" */ #include <stdio.h> static void scan(const char *fname); int main(int argc, char *argv[]) { if (argc != 2) { printf("Usage: %s file\n", argv[0]); exit(1); } scan(argv[1]); return 0; } #define READ_SIZE 4096 void scan(const char *fname) { FILE *fptr = fopen(fname, "rb"); long size = 0; char buff[READ_SIZE]; long idx; if (!fptr) { printf("can't open '%s'\n", fname); exit(1); } fseek(fptr, 0, SEEK_END); size = ftell(fptr); fseek(fptr, 0, SEEK_SET); printf("file size:\t%ld kb (%g meg)\n", size/1024, (float)size/(1024.0*1024.0)); for (idx = 0; idx < size/128 ; idx++) { long pos = rand() % (size - READ_SIZE); pos &= 0xFFFF1000; // benefit of the doubt... fseek(fptr, pos, SEEK_SET); if (fread(buff, READ_SIZE, 1, fptr) != 1) { printf("cant read at #%ld (pos: %ld)\n", idx, pos); exit(1); } } printf("total reads:\t%ld\n", size); fclose(fptr); } _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

1 0