Re: Initializing a NSMutableString an odd way
On 31.07.2013, at 22:01, Greg Parker gpar...@apple.com wrote:
On Jul 31, 2013, at 12:28 PM, Vincent Habchi vi...@macports.org wrote:
David Duncan wrote:
Why would there be? Your just asking for a mutable copy of an empty string.
It should be equivalent to [[NSMutableString alloc] initWithString:@« »]
But much slower I expect, since it creates a NSString, takes a mutable copy,
then implicitly releases the constant empty NSString.
For giggles I tried some NSMutableString allocation patterns into my
microbenchmark test harness.
Simple alloc/init is the fastest:
100 [[[NSMutableString alloc] init] release]
102 [[NSMutableString new] release]
109 [NSMutableString string] // ARC enabled
117 [[@ mutableCopy] release]
119 @autoreleasepool { [NSMutableString string]; } // ARC disabled
129 [[[NSMutableString alloc] initWithString:@] release]
(Smaller numbers are better. Numbers are getrusage(RUSAGE_SELF) time for
1000 iterations, normalized to fastest=100. Your mileage may vary.)
How much time contributes the allocation of the raw storage? I would guess that
initializing an empty string is quite fast (while generally NSString is
disappointing slow in almost all other functions).
What's also interesting is the time it takes to *deallocate* an object. Since
ARC and weak pointers, this time increased dramatically (due to the requirement
to remove the object from the sparse array).
In those micro-benchmarks its also interesting how this benchmark affects the
behavior of the heap. It's likely we see a particular edge case which is either
fast or slow. I would expect that allocating and deallocating the same object
in a loop leads to faster allocation times. As opposed to the case where
differrent objects are allocated and deallocated in random order.
Andreas
ARC and non-ARC scores are the same within measurement noise, except for
[NSMutableString string] where ARC can optimize the autoreleased return value
so the test doesn't need to spin the autorelease pool. Note th
BTW, what’s the difference between [[NSMutableString alloc] init] and
[[NSMutableString alloc] initWithString:@“”]?
Semantically there's no difference: you get the same string with the same
retain count.
--
Greg Parker gpar...@apple.com Runtime Wrangler
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Initializing a NSMutableString an odd way
Folks, I apologize if this question looks stupid or contrived. Here it is: is it permissible to use [@“” mutableCopy] to initialize (or reset) a NSMutableString instead of the more classical [[NSMutableString alloc] init]? Thanks a lot! Vincent ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On 31 Jul 2013, at 19:09, Vincent Habchi vi...@macports.org wrote: Folks, I apologize if this question looks stupid or contrived. Here it is: is it permissible to use [@“” mutableCopy] to initialize (or reset) a NSMutableString instead of the more classical [[NSMutableString alloc] init]? Yes. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
Le 31 juil. 2013 à 20:15, Mike Abdullah mabdul...@karelia.com a écrit : I apologize if this question looks stupid or contrived. Here it is: is it permissible to use [@“” mutableCopy] to initialize (or reset) a NSMutableString instead of the more classical [[NSMutableString alloc] init]? Yes. Thanks! (No side effect?) Vincent ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On Jul 31, 2013, at 11:25 AM, Vincent Habchi vi...@macports.org wrote: Le 31 juil. 2013 à 20:15, Mike Abdullah mabdul...@karelia.com a écrit : I apologize if this question looks stupid or contrived. Here it is: is it permissible to use [@“” mutableCopy] to initialize (or reset) a NSMutableString instead of the more classical [[NSMutableString alloc] init]? Yes. Thanks! (No side effect?) Why would there be? Your just asking for a mutable copy of an empty string. It should be equivalent to [[NSMutableString alloc] initWithString:@] -- David Duncan ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On 31 Jul 2013, at 1:28 PM, David Duncan david.dun...@apple.com wrote: On Jul 31, 2013, at 11:25 AM, Vincent Habchi vi...@macports.org wrote: Le 31 juil. 2013 à 20:15, Mike Abdullah mabdul...@karelia.com a écrit : I apologize if this question looks stupid or contrived. Here it is: is it permissible to use [@“” mutableCopy] to initialize (or reset) a NSMutableString instead of the more classical [[NSMutableString alloc] init]? Yes. Thanks! (No side effect?) Why would there be? Your just asking for a mutable copy of an empty string. It should be equivalent to [[NSMutableString alloc] initWithString:@] Or [NSMutableString string]. — F ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On Jul 31, 2013, at 1:45 PM, Fritz Anderson wrote: On 31 Jul 2013, at 1:28 PM, David Duncan david.dun...@apple.com wrote: On Jul 31, 2013, at 11:25 AM, Vincent Habchi vi...@macports.org wrote: Le 31 juil. 2013 à 20:15, Mike Abdullah mabdul...@karelia.com a écrit : I apologize if this question looks stupid or contrived. Here it is: is it permissible to use [@“” mutableCopy] to initialize (or reset) a NSMutableString instead of the more classical [[NSMutableString alloc] init]? Yes. Thanks! (No side effect?) Why would there be? Your just asking for a mutable copy of an empty string. It should be equivalent to [[NSMutableString alloc] initWithString:@] Or [NSMutableString string]. With ARC, yes. With MRR, they're different in terms of ownership. Regards, Ken ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
Thanks to all for answering, Why would there be? Your just asking for a mutable copy of an empty string. It should be equivalent to [[NSMutableString alloc] initWithString:@« »] But much slower I expect, since it creates a NSString, takes a mutable copy, then implicitly releases the constant empty NSString. BTW, what’s the difference between [[NSMutableString alloc] init] and [[NSMutableString alloc] initWithString:@“”]? Vincent ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
I think there are some overlooked subtleties as @ is a string literal. Retain and release are pretty much meaningless to it. Sandor Szatmari On Jul 31, 2013, at 15:28, Vincent Habchi vi...@macports.org wrote: Thanks to all for answering, Why would there be? Your just asking for a mutable copy of an empty string. It should be equivalent to [[NSMutableString alloc] initWithString:@« »] But much slower I expect, since it creates a NSString, takes a mutable copy, then implicitly releases the constant empty NSString. BTW, what’s the difference between [[NSMutableString alloc] init] and [[NSMutableString alloc] initWithString:@“”]? Vincent ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/admin.szatmari.net%40gmail.com This email sent to admin.szatmari@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On 31 Jul 2013, at 2:28 PM, Vincent Habchi vi...@macports.org wrote: Thanks to all for answering, Why would there be? Your just asking for a mutable copy of an empty string. It should be equivalent to [[NSMutableString alloc] initWithString:@« »] But much slower I expect, since it creates a NSString, takes a mutable copy, then implicitly releases the constant empty NSString. NSString literals are baked into the application binary, and couldn't be deallocated if you tried. They are interned, so the code sample at the end of this message prints the same addresses for foo and empty no matter how you use them (even the product of -copy). BTW, what’s the difference between [[NSMutableString alloc] init] and [[NSMutableString alloc] initWithString:@“”]? The latter is redundant. — F ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On Jul 31, 2013, at 12:28 PM, Vincent Habchi vi...@macports.org wrote:
David Duncan wrote:
Why would there be? Your just asking for a mutable copy of an empty string.
It should be equivalent to [[NSMutableString alloc] initWithString:@« »]
But much slower I expect, since it creates a NSString, takes a mutable copy,
then implicitly releases the constant empty NSString.
For giggles I tried some NSMutableString allocation patterns into my
microbenchmark test harness.
Simple alloc/init is the fastest:
100 [[[NSMutableString alloc] init] release]
102 [[NSMutableString new] release]
109 [NSMutableString string] // ARC enabled
117 [[@ mutableCopy] release]
119 @autoreleasepool { [NSMutableString string]; } // ARC disabled
129 [[[NSMutableString alloc] initWithString:@] release]
(Smaller numbers are better. Numbers are getrusage(RUSAGE_SELF) time for
1000 iterations, normalized to fastest=100. Your mileage may vary.)
ARC and non-ARC scores are the same within measurement noise, except for
[NSMutableString string] where ARC can optimize the autoreleased return value
so the test doesn't need to spin the autorelease pool. Note th
BTW, what’s the difference between [[NSMutableString alloc] init] and
[[NSMutableString alloc] initWithString:@“”]?
Semantically there's no difference: you get the same string with the same
retain count.
--
Greg Parker gpar...@apple.com Runtime Wrangler
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Re: Initializing a NSMutableString an odd way
On 7/31/2013 1:01 PM, Greg Parker gpar...@apple.com wrote:
Simple alloc/init is the fastest:
100 [[[NSMutableString alloc] init] release]
102 [[NSMutableString new] release]
109 [NSMutableString string] // ARC enabled
117 [[@ mutableCopy] release]
119 @autoreleasepool { [NSMutableString string]; } // ARC disabled
129 [[[NSMutableString alloc] initWithString:@] release]
(Smaller numbers are better. Numbers are getrusage(RUSAGE_SELF) time for
1000 iterations, normalized to fastest=100. Your mileage may vary.)
Yeah, those numbers make sense from a theoretical standpoint (i.e.
without looking at the source code). The +new call theoretically calls
+alloc/-init so would be slightly slower due to three method calls
(+new/+alloc/-init) and the -init call theoretically can do very little
until actual data is supplied while the others with actual data might add
the overhead of defining the actual data; theoretically, an empty string
is more data than no data yet to be filled.
--
Gary L. Wade
http://www.garywade.com/
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Re: Initializing a NSMutableString an odd way
Greg, thanks for diverting some of your time testing this. As someone already commented, the results are somehow consistent with “common sense”, whatever that means (cf. below). ARC and non-ARC scores are the same within measurement noise, except for [NSMutableString string] where ARC can optimize the autoreleased return value so the test doesn't need to spin the autorelease pool. Note th The end of your message somehow got lost in the cyberspace. I thus suppose that to “clean” a NSMutableString, it is faster to recreate another one rather than use -deleteCharactersInRange: with a range covering the whole string. Thanks again so much to everybody for your enlightening advice. Vincent — “Common sense is the collection of prejudices acquired by age eighteen.” A. Einstein. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On Jul 31, 2013, at 1:32 PM, Vincent Habchi vi...@macports.org wrote: Greg Parker wrote: ARC and non-ARC scores are the same within measurement noise, except for [NSMutableString string] where ARC can optimize the autoreleased return value so the test doesn't need to spin the autorelease pool. Note th The end of your message somehow got lost in the cyberspace. The spurious text was an editing error. No content was harmed. I thus suppose that to “clean” a NSMutableString, it is faster to recreate another one rather than use -deleteCharactersInRange: with a range covering the whole string. Not necessarily. If you have long string and you want to clear it and re-fill it with another long string, then it may be faster to use -deleteCharactersInRange: in order to avoid memory re-allocation overhead. But that possibility depends on precise implementation details of NSMutableString. -- Greg Parker gpar...@apple.com Runtime Wrangler ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
Why not [aMutableString setString:@];? Sandor Szatmari On Jul 31, 2013, at 16:32, Vincent Habchi vi...@macports.org wrote: Greg, thanks for diverting some of your time testing this. As someone already commented, the results are somehow consistent with “common sense”, whatever that means (cf. below). ARC and non-ARC scores are the same within measurement noise, except for [NSMutableString string] where ARC can optimize the autoreleased return value so the test doesn't need to spin the autorelease pool. Note th The end of your message somehow got lost in the cyberspace. I thus suppose that to “clean” a NSMutableString, it is faster to recreate another one rather than use -deleteCharactersInRange: with a range covering the whole string. Thanks again so much to everybody for your enlightening advice. Vincent — “Common sense is the collection of prejudices acquired by age eighteen.” A. Einstein. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/admin.szatmari.net%40gmail.com This email sent to admin.szatmari@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
Le 31 juil. 2013 à 22:38, Greg Parker gpar...@apple.com a écrit : Not necessarily. If you have long string and you want to clear it and re-fill it with another long string, then it may be faster to use -deleteCharactersInRange: in order to avoid memory re-allocation overhead. But that possibility depends on precise implementation details of NSMutableString. So I guess profiling is once more everybody’s friend. Thanks anyhow once more for taking the time to answer my very minor inquiry. Vincent ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Initializing a NSMutableString an odd way
On Jul 31, 2013, at 4:01 PM, Greg Parker wrote:
On Jul 31, 2013, at 12:28 PM, Vincent Habchi vi...@macports.org wrote:
David Duncan wrote:
Why would there be? Your just asking for a mutable copy of an empty string.
It should be equivalent to [[NSMutableString alloc] initWithString:@« »]
But much slower I expect, since it creates a NSString, takes a mutable copy,
then implicitly releases the constant empty NSString.
For giggles I tried some NSMutableString allocation patterns into my
microbenchmark test harness.
I'm rather fascinated with these and wrote the one that profiled the speed of
all variable classes and functions of Lingo back in the Director days.
Once we knew just how fast each of the variable allocations and functions took
when compared to each other, this made it really easy to determine what
approaches not to use in the interests of performance, or where we could change
code for the sake of readability over performance.
By any chance is this harness open or is it a private project? Of course, we
have instruments, but it would be rather great to simply be able to plug in
some operations and know the speed of them and their speed relative to each
other.
Simple alloc/init is the fastest:
100 [[[NSMutableString alloc] init] release]
102 [[NSMutableString new] release]
109 [NSMutableString string] // ARC enabled
117 [[@ mutableCopy] release]
119 @autoreleasepool { [NSMutableString string]; } // ARC disabled
129 [[[NSMutableString alloc] initWithString:@] release]
(Smaller numbers are better. Numbers are getrusage(RUSAGE_SELF) time for
1000 iterations, normalized to fastest=100. Your mileage may vary.)
ARC and non-ARC scores are the same within measurement noise, except for
[NSMutableString string] where ARC can optimize the autoreleased return value
so the test doesn't need to spin the autorelease pool. Note th
Your note got cut off near the en
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