How to implement immutable ring buffer?
Could somebody share his thoughts on the subject? Would it be efficient? Is it possible to avoid memory copying to provide immutability? To avoid cache missing ring buffer should be like array, not list, so it's possible that the whole buffer should be moved. Is it neccessary to be real immutable, may be some form of fake immutabitiy is enough? I'd like to try immutability in my app, and ring buffer is what I don't know how to use in the realm of immutability. Thanks
Re: problem with gc?
On Wednesday, 27 May 2015 at 08:42:01 UTC, zhmt wrote: When I enable the --profle, get something like this, it doesnt give me too much help: [...] Tried callgrind and kcachegrind? If nothing else it's better at illustrating the same output, assuming you have graphviz/dot installed. Given --dump-instr you can also get instruction-level profiling if you're really wondering what's happening.
Re: problem with gc?
On Wednesday, 27 May 2015 at 09:39:42 UTC, Anonymouse wrote: On Wednesday, 27 May 2015 at 08:42:01 UTC, zhmt wrote: When I enable the --profle, get something like this, it doesnt give me too much help: [...] Tried callgrind and kcachegrind? If nothing else it's better at illustrating the same output, assuming you have graphviz/dot installed. Given --dump-instr you can also get instruction-level profiling if you're really wondering what's happening. @Anonymouse Thank u very much, I have tried this: valgrind --tool=callgrind ./gamelibdtest callgrind_annotate callgrind.out.29234 Ir file:function 124,918,002 ???:_D9invariant12_d_invariantFC6ObjectZv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 27,235,809 ???:_D2gc2gc2GC6mallocMFNbmkPmxC8TypeInfoZPv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 22,484,758 /mnt/hgfs/mydoc/dworkspace/gamelibdtest//usr/include/dmd/phobos/std/format.d:_D3std6format74__T14formatUnsignedTS3std6format16__T7sformatTaTiZ7sformatFAaxAaiZ4SinkTaZ14formatUnsignedFNaNfS3std6format16__T7sformatTaTiZ7sformatFAaxAaiZ4SinkmKS3std6format18__T10FormatSpecTaZ10FormatSpeckbZv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 19,171,341 ???:_D2gc2gc3Gcx10smallAllocMFNbhKmkZPv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 16,334,730 ???:pthread_mutex_lock [/usr/lib64/libpthread-2.17.so] 14,519,760 ???:pthread_mutex_unlock [/usr/lib64/libpthread-2.17.so] 14,503,272 /mnt/hgfs/mydoc/dworkspace/gamelibdtest/../gamelibd/source/gamelibd/net/linux/epollapi.d:_D8gamelibd3net5linux8epollapi8bitExistFiiZb [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 13,521,278 /mnt/hgfs/mydoc/dworkspace/gamelibdtest/../gamelibd/source/gamelibd/net/linux/TcpLinuxConn.d:_D8gamelibd3net5linux12TcpLinuxConn12TcpLinuxConn8readSomeMFAhZi'2 [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 12,695,373 ???:_D2gc2gc3Gcx10smallAllocMFNbhKmkZ8tryAllocMFNbZb [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 12,558,147 /mnt/hgfs/mydoc/dworkspace/gamelibdtest/../gamelibd/source/gamelibd/net/linux/linuxconn.d:_D8gamelibd3net5linux9linuxconn11handleEventFAS8gamelibd3net5linux8epollapi11epoll_eventZv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 12,091,173 ???:_D4core6thread5Fiber39__T4callVE4core6thread5Fiber7Rethrowi1Z4callMFZC6object9Throwable [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 11,153,058 /mnt/hgfs/mydoc/dworkspace/gamelibdtest//usr/include/dmd/phobos/std/format.d:_D3std6format18__T10FormatSpecTaZ10FormatSpec75__T17writeUpToNextSpecTS3std6format16__T7sformatTaTiZ7sformatFAaxAaiZ4SinkZ17writeUpToNextSpecMFNaNfS3std6format16__T7sformatTaTiZ7sformatFAaxAaiZ4SinkZb [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 10,877,409 /mnt/hgfs/mydoc/dworkspace/gamelibdtest/../gamelibd/source/gamelibd/net/linux/epollapi.d:_D8gamelibd3net5linux8epollapi8changeEvFiiPviZv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 10,676,006 /mnt/hgfs/mydoc/dworkspace/gamelibdtest/../gamelibd/source/gamelibd/net/linux/TcpLinuxConn.d:_D8gamelibd3net5linux12TcpLinuxConn12TcpLinuxConn9writeSomeMFAhZi [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 10,279,096 ???:pthread_getspecific [/usr/lib64/libpthread-2.17.so] 9,741,852 ???:__GI_memset [/usr/lib64/libc-2.17.so] 9,645,888 ???:_d_arraycopy [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 9,430,244 ???:_D2gc2gc3Gcx5sweepMFNbZm [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 8,866,869 ???:_D4core6atomic50__T11atomicStoreVE4core6atomic11MemoryOrderi0TbTbZ11atomicStoreFNaNbNiKObbZv [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest] 8,661,662 /mnt/hgfs/mydoc/dworkspace/gamelibdtest/../gamelibd/source/gamelibd/net/linux/TcpLinuxConn.d:_D8gamelibd3net5linux12TcpLinuxConn12TcpLinuxConn5writeMFAhZi [/mnt/hgfs/mydoc/dworkspace/bin/gamelibdtest]
Re: problem with gc?
When I enable the --profle, get something like this, it doesnt give me too much help: Timer Is 3579545 Ticks/Sec, Times are in Microsecs Num TreeFuncPer CallsTimeTimeCall 1298756 4996649885 49875773773840 int gamelibd.net.linux.TcpLinuxConn.TcpLinuxConn.writeSome(ubyte[]) 30358909 14353678347 4433441425 146 void gamelibd.net.linux.linuxconn.selectAndProcessNetEvents(ulong) 30359249 1670090296 1582462941 52 long gamelibd.util.utcNow() 1298744 874889280 858583339 661 _D8gamelibd3net5linux12TcpLinuxConn12TcpLinuxConn8readSomeMFAhZ9__lambda2MFZv 1300549 25997 803742026 618 int gamelibd.net.linux.TcpLinuxConn.TcpLinuxConn.readSome(ubyte[]) 2597506 756203332 702092233 270 void gamelibd.net.linux.epollapi.changeEv(int, int, void*, int) 30358909 9920075665 285890739 9 void gamelibd.net.linux.linuxconn.handleEvent(gamelibd.net.linux.epollapi.epoll_event[]) 1298744 5131800498 244989946 188 void gamelibd.net.linux.TcpLinuxConn.TcpLinuxConn.doRead(gamelibd.net.linux.epollapi.epoll_event*) 1298768 0 223952199 172 void gamelibd.net.linux.IoEventHandler.IoEventHandler.autoReaderFiberSetting(void delegate()) 1298756 5207337081 210684924 162 int gamelibd.net.linux.TcpLinuxConn.TcpLinuxConn.write(ubyte[]) 30358953 162443804 162443804 5 @property bool gamelibd.util.LinkedList!(gamelibd.net.exceptionsafefiber.ExceptionSafeFiber).LinkedList.isEmpty() 648485 989705094 139972636 215 int gamelibd.net.linux.TcpLinuxConn.TcpLinuxConn.read(ubyte[]) 1298919 1008643391 124807374 96 void gamelibd.net.exceptionsafefiber.ExceptionSafeFiber.resume() 303590728843187288431872 2 pure nothrow @nogc @safe gamelibd.net.exceptionsafefiber.TimerTask std.container.rbtree.__T12RedBlackTreeTC8gamelibd3net18exceptionsafefiber9TimerTaskVAyaa25_612e737461727454696d65203c20622e737461727454696d65Vbi1Z.RedBlackTree.front() 1298750 157489732887384898 67 void gamelibd.net.linux.IoEventHandler.IoEventHandler.tryResumeReaderFiber() 303590727732591577325915 2 pure nothrow @property @nogc @safe ulong std.container.rbtree.__T12RedBlackTreeTC8gamelibd3net18exceptionsafefiber9TimerTaskVAyaa25_612e737461727454696d65203c20622e737461727454696d65Vbi1Z.RedBlackTree.length() 45448316156034761560347 13 pure @safe bool std.exception.enforce!(bool).enforce(bool, lazy object.Throwable) 25975005190564251905642 19 void gamelibd.net.linux.TcpLinuxConn.TcpLinuxConn.throwExceptionIfErrAfterOp(long) 12989514939205649392056 38 gamelibd.net.exceptionsafefiber.ExceptionSafeFiber gamelibd.net.exceptionsafefiber.ExceptionSafeFiber.getThis() 25975188087718146297298 17 gamelibd.mem.Ptr!(gamelibd.net.provider.Conn).Ptr.getinout(ref @property inout(gamelibd.net.provider.Conn) function()) 25976935172573037629038 14 gamelibd.mem.Ptr!(gamelibd.net.exceptionsafefiber.ExceptionSafeFiber).Ptr.getinout(ref @property inout(gamelibd.net.exceptionsafefiber.ExceptionSafeFiber) function()) 1298756 47994165534717468 26 void gamelibd.net.linux.IoEventHandler.IoEventHandler.enableRead()
Re: How to implement immutable ring buffer?
On 27.05.2015 11:04, thedeemon wrote: This whole idea sounds self-contradictory. Ring buffer is a mutable-array-based implementation of something, for example of a queue. You can ask about immutable implementations of a queue, but that would be another question, not involving a ring buffer. What do you want to do with this buffer, what do you need it for? In general I need to have the last n instances of some objects queue. Now it implemented using ring buffer. Probably, you're right about immutable queue, it is more suitable definition here.
Re: problem with gc?
@jklp
And also you could try to surround the whole block with
`GC.disable` and `GC.enable`. This would help to determine if
the GC is involved:
---
Ptr!Conn conn = connect(127.0.0.1,8881);
GC.disable;
ubyte[100] buf;
string str;
for(int i=0; iN; i++)
{
str = format(%s,i);
conn.write(cast(ubyte[]) str);
conn.read(buf[0..str.length]);
n++;
}
GC.enable;
conn.close();
---
I have tried this, and throughput falls down as well too. Does
this mean the gc is not involved? I am confused.
Re: How to implement immutable ring buffer?
On Wed, 27 May 2015 09:20:52 + drug via Digitalmars-d-learn digitalmars-d-learn@puremagic.com wrote: Could somebody share his thoughts on the subject? Would it be efficient? Is it possible to avoid memory copying to provide immutability? To avoid cache missing ring buffer should be like array, not list, so it's possible that the whole buffer should be moved. Is it neccessary to be real immutable, may be some form of fake immutabitiy is enough? I'd like to try immutability in my app, and ring buffer is what I don't know how to use in the realm of immutability. Thanks Maybe http://dlang.org/phobos/std_typecons.html#.Rebindable could help you.
Re: problem with gc?
On Wednesday, 27 May 2015 at 10:24:59 UTC, zhmt wrote: @Anonymouse Thank u very much, I have tried this: valgrind --tool=callgrind ./gamelibdtest callgrind_annotate callgrind.out.29234 Ir file:function [...] Without touching on the actual profile (which I'll leave to those better knowledgeable than I), open those callgrind.out.pid.* files in KCachegrind to get callgraphs. See https://imgur.com/AZEutCE,XXIDBvB,qehWaHg,bpTxS,3YfcJdh for some examples.
Re: How to implement immutable ring buffer?
This whole idea sounds self-contradictory. Ring buffer is a mutable-array-based implementation of something, for example of a queue. You can ask about immutable implementations of a queue, but that would be another question, not involving a ring buffer. What do you want to do with this buffer, what do you need it for?
Re: problem with gc?
What happened when the code changes a little? Who will give an
explaination,Thanks a lot?
what happend if you use sformat instead?
Ptr!Conn conn = connect(127.0.0.1,8881);
ubyte[100] buf;
char[100] buf2;
for(int i=0; iN; i++)
{
auto str = sformat(buf2, %s,i);
conn.write((cast(ubyte*)str.ptr)[0..str.length]);
conn.read(buf[0..str.length]);
n++;
}
conn.close();
@Daniel Kozák
Thanks for reply.
I have tried sformat, but it doesnt work: throughput falls down,
and the cpu keeps busy.
Re: problem with gc?
If I pass a timeout with 1ms to epoll_wait,the cpu will not be busy when throughput falls down.
Re: problem with gc?
It seems that dlang library is not so effient?
Re: How to implement immutable ring buffer?
On 27.05.2015 11:10, Daniel Kozák via Digitalmars-d-learn wrote: On Wed, 27 May 2015 09:20:52 + drug via Digitalmars-d-learn digitalmars-d-learn@puremagic.com wrote: Could somebody share his thoughts on the subject? Would it be efficient? Is it possible to avoid memory copying to provide immutability? To avoid cache missing ring buffer should be like array, not list, so it's possible that the whole buffer should be moved. Is it neccessary to be real immutable, may be some form of fake immutabitiy is enough? I'd like to try immutability in my app, and ring buffer is what I don't know how to use in the realm of immutability. Thanks Maybe http://dlang.org/phobos/std_typecons.html#.Rebindable could help you. I guess it won't be efficient, because it would be ring buffer of (in some form) pointers. It's suitable if elements of the buffer are processed independently each other. In other case cache misses are provided, I think.
Re: problem with gc?
On 5/27/15 2:42 AM, zhmt wrote: When I enable the --profle, get something like this, it doesnt give me too much help: I don't see any GC function here, I don't think you are are focusing on the right portion of the code. Seems like the gamelib library is consuming all the time. You may want to check with the author of that code for help. -Steve
Null argument and function resolution
Check this example:
http://dpaste.dzfl.pl/53f85bae4382
Calling with null, both c-tor match.
Is there a way to solve this?
Something like:
this(in ubyte* data) if( ??? )
{
}
Andrea
Re: problem with gc?
On Wednesday, 27 May 2015 at 10:27:08 UTC, zhmt wrote: It seems that dlang library is not so effient? The gamelibd could be doing a lot more than just echoing... it sounds to me that your socket might be blocking and epoll is busy looping waiting for it to become available again.
Re: Prevent slices from referencing old array after realocation?
On 5/27/15 1:55 AM, Gr8Ape wrote: I'm writing a program that handles lots of slices of larger arrays. I need the data of each of them all together for one operation, but otherwise it's more convenient to handle the elements in small groups. I could just store a pointer to my array, an offset, and a length but since I'm using D I'd much prefer to use slices... So I was looking through the documentation on slices and found out that if the array has to realocate then slices pointing to that array will keep on pointing to that block of memory, rather than the new location. Given that I'll be working with arrays that can vary wildly in size and that giving all of them the maximum capacity so they never realocate would be extremely inefficent, I need a workaround. So I'm wondering if there's a way to tell all the slices of an underlying array to now point to the new underlying array upon reallocation? Or would I have to iterate through and reassign every slice? Slices can't do this, because they have no idea about each other. So when you append to one slice, you can't have it update all other relevant slices. However, you could create a type that does this. -Steve
problem with custom predicate
I am trying to use a Container class with a custom predicate, but
the following code does not compile. Any hints on how to do it?
import std.container;
class C
{
int[] prio;
RedBlackTree!(int, (a,b)=prio[a]prio[b]) tree;
}
I think I understand the reason why this does not work (the
lambda cannot access the 'this' to get to 'prio'), but I can't
think of a way to make it work. Any Ideas?
Re: Null argument and function resolution
Two options:
1) add an overload that takes typeof(null)
this(typeof(null)) { /* handles the null literal specially */ }
2) Cast null to a specific type when making it:
new YourClass(cast(ubyte*) null);
Re: problem with custom predicate
On 5/27/15 9:59 AM, Meta wrote: I thought unaryFun *does* work with all callables, including structs/classes with opCall? It (binaryFun actually) declares an alias. But you need an actual instance to use in this case. You simply can't declare that in a type definition, and it won't be set up properly in the constructor even if you could. You need an instance in order to use an alias to that instance. What likely would happen is if the functor is a callable type, and that type is not a functor itself (i.e. doesn't define static opCall), is that RedBlackTree would then require an instance of that type as part of the constructor. -Steve
Re: problem with gc?
On Wednesday, 27 May 2015 at 05:48:13 UTC, zhmt wrote: The code you posted is the client code, but the issue seems to be on the server side. Can you post the server code and also the timing code?
Re: Prevent slices from referencing old array after realocation?
On Wednesday, 27 May 2015 at 07:55:29 UTC, Gr8Ape wrote: You can keep an index and a count instead of a slice. If you know your data well, you can exploit this knowledge, and this has the potential to save you many bytes per slice when dealing with large data sets. Depending on your access patterns, it also has the potential to be fairly more cpu-efficient.
Re: problem with custom predicate
On 5/27/15 9:11 AM, Simon =?UTF-8?B?QsO8cmdlciI=?= simon.buer...@rwth-aachen.de wrote: On Wednesday, 27 May 2015 at 14:58:39 UTC, drug wrote: Do you want to dynamically change priority? Actually yes. In my actual code I am not using a RedBlackTree but my own Container (a heap with the possibility to modify elements inside), which is notified when prio changes so it can do a (local) reordering. It would be a very bad idea to change prio if the RBTree is constructed already (and if this works). Why prio is outside of your predicate? Well, how would I get it into the lambda? In C++ I would use a comparision class, and the constructor of the container would take an instance of that class. But D's RedBlackTree-constructor does not take such a (run-time) argument. And I dont see a way to get prio into the predicate, which is a template-argument. This is true, RedBlackTree does not take a functor as a parameter to the constructor, it just uses an alias. This should work if your RedBlackTree is scoped inside a function where the data exists. But at the time of declaration inside the class, the instance of prio doesn't exist, so you can't alias it. It would be a good enhancement I think to add support for function objects. -Steve
Re: problem with custom predicate
On 05/27/2015 05:30 PM, Steven Schveighoffer wrote: On 5/27/15 9:11 AM, Simon =?UTF-8?B?QsO8cmdlciI=?= simon.buer...@rwth-aachen.de wrote: On Wednesday, 27 May 2015 at 14:58:39 UTC, drug wrote: Do you want to dynamically change priority? Actually yes. In my actual code I am not using a RedBlackTree but my own Container (a heap with the possibility to modify elements inside), which is notified when prio changes so it can do a (local) reordering. It would be a very bad idea to change prio if the RBTree is constructed already (and if this works). Why prio is outside of your predicate? Well, how would I get it into the lambda? In C++ I would use a comparision class, and the constructor of the container would take an instance of that class. But D's RedBlackTree-constructor does not take such a (run-time) argument. And I dont see a way to get prio into the predicate, which is a template-argument. This is true, RedBlackTree does not take a functor as a parameter to the constructor, it just uses an alias. This should work if your RedBlackTree is scoped inside a function where the data exists. But at the time of declaration inside the class, the instance of prio doesn't exist, so you can't alias it. It would be a good enhancement I think to add support for function objects. -Steve Also, apart from missing implementation, there is no good reason why the code given should not work, is there? I think nested template instantiation should work in all scopes. (Of course, there is the issue that nested structs are somewhat arbitrarily not given a context pointer when declared within a class/struct, so this might be a little inconsistent in case it also works for structs, no question for classes though: just instantiate as nested class.)
Re: problem with custom predicate
On Wednesday, 27 May 2015 at 15:30:28 UTC, Steven Schveighoffer wrote: On 5/27/15 9:11 AM, Simon =?UTF-8?B?QsO8cmdlciI=?= simon.buer...@rwth-aachen.de wrote: On Wednesday, 27 May 2015 at 14:58:39 UTC, drug wrote: Do you want to dynamically change priority? Actually yes. In my actual code I am not using a RedBlackTree but my own Container (a heap with the possibility to modify elements inside), which is notified when prio changes so it can do a (local) reordering. It would be a very bad idea to change prio if the RBTree is constructed already (and if this works). Why prio is outside of your predicate? Well, how would I get it into the lambda? In C++ I would use a comparision class, and the constructor of the container would take an instance of that class. But D's RedBlackTree-constructor does not take such a (run-time) argument. And I dont see a way to get prio into the predicate, which is a template-argument. This is true, RedBlackTree does not take a functor as a parameter to the constructor, it just uses an alias. This should work if your RedBlackTree is scoped inside a function where the data exists. But at the time of declaration inside the class, the instance of prio doesn't exist, so you can't alias it. It would be a good enhancement I think to add support for function objects. -Steve I thought unaryFun *does* work with all callables, including structs/classes with opCall?
Re: Null argument and function resolution
The first answer is the one I was looking for. Very useful.
You should add to next this week in d tips.
On Wednesday, 27 May 2015 at 14:09:48 UTC, Adam D. Ruppe wrote:
Two options:
1) add an overload that takes typeof(null)
this(typeof(null)) { /* handles the null literal specially */ }
2) Cast null to a specific type when making it:
new YourClass(cast(ubyte*) null);
Re: problem with custom predicate
On 27.05.2015 13:50, Simon Bürger simon.buer...@rwth-aachen.de wrote:
I am trying to use a Container class with a custom predicate, but the
following code does not compile. Any hints on how to do it?
import std.container;
class C
{
int[] prio;
RedBlackTree!(int, (a,b)=prio[a]prio[b]) tree;
}
I think I understand the reason why this does not work (the lambda
cannot access the 'this' to get to 'prio'), but I can't think of a way
to make it work. Any Ideas?
Do you want to dynamically change priority? Why prio is outside of your
predicate?
Re: problem with custom predicate
On Wednesday, 27 May 2015 at 14:58:39 UTC, drug wrote: Do you want to dynamically change priority? Actually yes. In my actual code I am not using a RedBlackTree but my own Container (a heap with the possibility to modify elements inside), which is notified when prio changes so it can do a (local) reordering. Why prio is outside of your predicate? Well, how would I get it into the lambda? In C++ I would use a comparision class, and the constructor of the container would take an instance of that class. But D's RedBlackTree-constructor does not take such a (run-time) argument. And I dont see a way to get prio into the predicate, which is a template-argument. As I am implementing my own container anyway, I could of course do it the C++-way. But I was wondering if there is another way.
Re: Null argument and function resolution
On Wed, 27 May 2015 14:09:47 +, Adam D. Ruppe wrote:
Two options:
1) add an overload that takes typeof(null)
this(typeof(null)) { /* handles the null literal specially */ }
you keep breaking my box of thinking. ;-) never thought about such
declaration.
signature.asc
Description: PGP signature
Re: problem with custom predicate
On Wednesday, 27 May 2015 at 17:56:27 UTC, Steven Schveighoffer wrote: On 5/27/15 9:59 AM, Meta wrote: I thought unaryFun *does* work with all callables, including structs/classes with opCall? It (binaryFun actually) declares an alias. But you need an actual instance to use in this case. You simply can't declare that in a type definition, and it won't be set up properly in the constructor even if you could. You need an instance in order to use an alias to that instance. What likely would happen is if the functor is a callable type, and that type is not a functor itself (i.e. doesn't define static opCall), is that RedBlackTree would then require an instance of that type as part of the constructor. -Steve Yes, sorry, I meant binaryFun. I remember having a similar problem with tee, and decided to just disallow passing in the name of a struct/class with opCall as a template argument, and instead require that an instance is passed at runtime.
Re: Null argument and function resolution
On Wednesday, 27 May 2015 at 19:38:16 UTC, ketmar wrote:
On Wed, 27 May 2015 14:09:47 +, Adam D. Ruppe wrote:
Two options:
1) add an overload that takes typeof(null)
this(typeof(null)) { /* handles the null literal specially */ }
you keep breaking my box of thinking. ;-) never thought about
such
declaration.
Unfortunately, there is no equivalent way to disable assignment
of [] at compile time.
struct ArrayWrapper(T)
{
T[] a;
this(T[] arr) { a = arr; }
//Doesn't work; Conflicts with this(T[] arr)
//@disable this(typeof(this)[]);
//Doesn't work; hijacked by this(T[] arr)
//@disable this(typeof([]));
}
Re: Null argument and function resolution
On 05/27/2015 10:09 PM, Meta wrote:
On Wednesday, 27 May 2015 at 19:38:16 UTC, ketmar wrote:
On Wed, 27 May 2015 14:09:47 +, Adam D. Ruppe wrote:
Two options:
1) add an overload that takes typeof(null)
this(typeof(null)) { /* handles the null literal specially */ }
you keep breaking my box of thinking. ;-) never thought about such
declaration.
Unfortunately, there is no equivalent way to disable assignment of [] at
compile time.
struct ArrayWrapper(T)
{
T[] a;
this(T[] arr) { a = arr; }
//Doesn't work; Conflicts with this(T[] arr)
//@disable this(typeof(this)[]);
//Doesn't work; hijacked by this(T[] arr)
//@disable this(typeof([]));
}
https://issues.dlang.org/show_bug.cgi?id=7007
Re: problem with gc?
On Wednesday, 27 May 2015 at 05:51:21 UTC, zhmt wrote: I noticed that the cpu% falls from 99% down to 4% as well when the throughput falls down. I tried again for several times, the cpu is still busy, 98.9%.
Re: problem with gc?
I think it is not problem of gc, it is my fault: The operations is serialized: clent send - server recv - server send - client recv, so if one operation takes too long time, the throughput will definitely fall down. I cant explain why it so fast when buffer is big enough, and so low when buffer is smaller than data size.
Re: problem with gc?
On Wednesday, 27 May 2015 at 19:04:53 UTC, Márcio Martins wrote:
On Wednesday, 27 May 2015 at 05:48:13 UTC, zhmt wrote:
The code you posted is the client code, but the issue seems to
be on the server side.
Can you post the server code and also the timing code?
@Márcio Martins
here is the server code：
void echoServer()
{
Acceptor acc2 = new Acceptor();
acc2.listen(0.0.0.0,8881,100);
acc2.accept((Ptr!Conn c){
scope(exit) c.close();
ubyte[5] buf;
while(true)
{
int n = c.readSome(buf);
if(n=0){
break;
}
c.write(buf[0..n]);
}
writeFlush(close server sock);
});
}
and I found the reason：
the buffer size on server is too small， just five，so if the data
size is more than 5（1 for example），it will need two read
operation。
The length of “1” is 5，it perfectly matched the point of
falling down。
If change the buffer size to 100， it runs well。
But why it falls sharply down to about 24，I will continue to
study。
Template problem - if arg[0]==something; call arg[1];
I have some code that I'd really like to template-ize.
Currently, I've the same construct all over my code, repeated(yet
slightly different) about 15 times.
Too much for me, and I'd like to make it into a template.
This is a sample of my current code:
http://dpaste.dzfl.pl/76814846898e
I essentially want to change the
string helper(){
snip
foreach(child; toSpawn.children){
switch(child.name){
case NameOfArg1:
str ~= FunctionToCall1;
break;
case NameOfArg2:
str ~= FunctionToCall2;
break;
snip
}
function to something like:
handleParseTreeHelper!( string NameOfArg1, delegate
FunctionToCall1,
string NameOfArg2, delegate
FunctionToCall2 );
Any idears?
Re: Template problem - if arg[0]==something; call arg[1];
On Wed, 27 May 2015 22:49:18 +, ketmar wrote: i.e. `constructCases~(Aliases[2..$])` `constructCases!(Aliases[2..$])`, of course ;-) signature.asc Description: PGP signature
Re: Template problem - if arg[0]==something; call arg[1];
On Wed, 27 May 2015 22:35:54 +, wobbles wrote: quick looking thru your code raises two questions: 1. didn't you forgot to add `.stringof` in `constructCases`? 2. didn't you forgot `!` in `constructCases(Aliases[2..$])`? i.e. `constructCases~(Aliases[2..$])` it may work with that. signature.asc Description: PGP signature
Re: problem with gc?
On Wednesday, 27 May 2015 at 05:48:13 UTC, zhmt wrote: What happened when the code changes a little? Who will give an explaination,Thanks a lot? Yes, on the first sight it looks like your allocations in the loop make GC spend too much time. I don't think scope does anything here. Try adding delete str; to the end of the loop, it should do what your scope meant. I know it's deprecated but sometimes it's just right.
Re: problem with gc?
On Wednesday, 27 May 2015 at 05:48:13 UTC, zhmt wrote:
I am writing a echoclient, as below:
Ptr!Conn conn = connect(127.0.0.1,8881);
ubyte[100] buf;
for(int i=0; iN; i++)
{
scope string str = format(%s,i);
conn.write((cast(ubyte*)str.ptr)[0..str.length]);
conn.read(buf[0..str.length]);
n++;
}
conn.close();
When it loops about more than 10 times,the throughput will
fall from 6request/second to 26request/second.
If the code changes a little as below:
scope string str = format(%s,1); //changes to a constant
It will runs normally with speed of 6request/second. I test
for 13minutes, everything seems well.
What happened when the code changes a little? Who will give an
explaination,Thanks a lot?
Have you tried to declare str in the upper scope ?
---
Ptr!Conn conn = connect(127.0.0.1,8881);
ubyte[100] buf;
string str;
for(int i=0; iN; i++)
{
str = format(%s,i);
conn.write(cast(ubyte[]) str);
conn.read(buf[0..str.length]);
n++;
}
conn.close();
---
And also you could try to surround the whole block with
`GC.disable` and `GC.enable`. This would help to determine if the
GC is involved:
---
Ptr!Conn conn = connect(127.0.0.1,8881);
GC.disable;
ubyte[100] buf;
string str;
for(int i=0; iN; i++)
{
str = format(%s,i);
conn.write(cast(ubyte[]) str);
conn.read(buf[0..str.length]);
n++;
}
GC.enable;
conn.close();
---
Re: problem with gc?
On Wed, 27 May 2015 05:48:11 +
zhmt via Digitalmars-d-learn digitalmars-d-learn@puremagic.com wrote:
I am writing a echoclient, as below:
Ptr!Conn conn = connect(127.0.0.1,8881);
ubyte[100] buf;
for(int i=0; iN; i++)
{
scope string str = format(%s,i);
conn.write((cast(ubyte*)str.ptr)[0..str.length]);
conn.read(buf[0..str.length]);
n++;
}
conn.close();
When it loops about more than 10 times,the throughput will
fall from 6request/second to 26request/second.
If the code changes a little as below:
scope string str = format(%s,1); //changes to a constant
It will runs normally with speed of 6request/second. I test
for 13minutes, everything seems well.
What happened when the code changes a little? Who will give an
explaination,Thanks a lot?
what happend if you use sformat instead?
Ptr!Conn conn = connect(127.0.0.1,8881);
ubyte[100] buf;
char[100] buf2;
for(int i=0; iN; i++)
{
auto str = sformat(buf2, %s,i);
conn.write((cast(ubyte*)str.ptr)[0..str.length]);
conn.read(buf[0..str.length]);
n++;
}
conn.close();
Prevent slices from referencing old array after realocation?
I'm writing a program that handles lots of slices of larger arrays. I need the data of each of them all together for one operation, but otherwise it's more convenient to handle the elements in small groups. I could just store a pointer to my array, an offset, and a length but since I'm using D I'd much prefer to use slices... So I was looking through the documentation on slices and found out that if the array has to realocate then slices pointing to that array will keep on pointing to that block of memory, rather than the new location. Given that I'll be working with arrays that can vary wildly in size and that giving all of them the maximum capacity so they never realocate would be extremely inefficent, I need a workaround. So I'm wondering if there's a way to tell all the slices of an underlying array to now point to the new underlying array upon reallocation? Or would I have to iterate through and reassign every slice?
Re: problem with gc?
On Wednesday, 27 May 2015 at 05:48:13 UTC, zhmt wrote:
I am writing a echoclient, as below:
Ptr!Conn conn = connect(127.0.0.1,8881);
ubyte[100] buf;
for(int i=0; iN; i++)
{
scope string str = format(%s,i);
conn.write((cast(ubyte*)str.ptr)[0..str.length]);
conn.read(buf[0..str.length]);
n++;
}
conn.close();
You can use sformat
http://dlang.org/phobos/std_format.html#.sformat with your buffer.
