upstream/mercurial-mirror Files · contrib/fuzz/bdiff.cc

wireprotoframing: buffer emitted data to reduce frame count...

wireprotoframing: buffer emitted data to reduce frame count An upcoming commit introduces a wire protocol command that can emit hundreds of thousands of small objects. Without a buffering layer, we would emit a single, small frame for every object. Performance profiling revealed this to be a source of significant overhead for both client and server. This commit introduces a very crude buffering layer so that we emit fewer, bigger frames in such a scenario. This code will likely get rewritten in the future to be part of the streams API, as we'll need a similar strategy for compressing data. I don't want to think about it too much at the moment though. server before: user 32.500+0.000 sys 1.160+0.000 after: user 20.230+0.010 sys 0.180+0.000 client before: user 133.400+0.000 sys 93.120+0.000 after: user 68.370+0.000 sys 32.950+0.000 This appears to indicate we have significant overhead in the frame processing code on both client and server. It might be worth profiling that at some point... Differential Revision: https://phab.mercurial-scm.org/D4473

Augie Fackler - - Load All Authors

File last commit:

r38191:fa0ddd5e default


                r39596:84bf6ded

default

Download file

             bdiff.cc
        
                    44 lines
            
             | 1.0 KiB
            
                | text/x-c
            
             |
                CppLexer
            
             / contrib / fuzz / bdiff.cc
          
                    History
                
                 |
                  Annotation
                 | Raw
                 |Copy content
                 |Copy permalink

      /*

       * bdiff.cc - fuzzer harness for bdiff.c

       *

       * Copyright 2018, Google Inc.

       *

       * This software may be used and distributed according to the terms of

       * the GNU General Public License, incorporated herein by reference.

       */

      #include <memory>

      #include <stdlib.h>

      #include "fuzzutil.h"

      extern "C" {

      #include "bdiff.h"

      int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)

      {

      	auto maybe_inputs = SplitInputs(Data, Size);

      	if (!maybe_inputs) {

      		return 0;

      	}

      	auto inputs = std::move(maybe_inputs.value());

      	struct bdiff_line *a, *b;

      	int an = bdiff_splitlines(inputs.left.get(), inputs.left_size, &a);

      	int bn = bdiff_splitlines(inputs.right.get(), inputs.right_size, &b);

      	struct bdiff_hunk l;

      	bdiff_diff(a, an, b, bn, &l);

      	free(a);

      	free(b);

      	bdiff_freehunks(l.next);

      	return 0; // Non-zero return values are reserved for future use.

      }

      #ifdef HG_FUZZER_INCLUDE_MAIN

      int main(int argc, char **argv)

      {

      	const char data[] = "asdf";

      	return LLVMFuzzerTestOneInput((const uint8_t *)data, 4);

      }

      #endif

      } // extern "C"

	Site-wide shortcuts
/	Use quick search box
g h	Goto home page
g g	Goto my private gists page
g G	Goto my public gists page
g 0-9	Goto bookmarked items from 0-9
n r	New repository page
n g	New gist page

	Repositories
g s	Goto summary page
g c	Goto changelog page
g f	Goto files page
g F	Goto files page with file search activated
g p	Goto pull requests page
g o	Goto repository settings
g O	Goto repository access permissions settings
t s	Toggle sidebar on some pages

				/*
				* bdiff.cc - fuzzer harness for bdiff.c
				*
				* Copyright 2018, Google Inc.
				*
				* This software may be used and distributed according to the terms of
				* the GNU General Public License, incorporated herein by reference.
				*/
				#include <memory>
				#include <stdlib.h>

				#include "fuzzutil.h"

				extern "C" {
				#include "bdiff.h"

				int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
				{
				auto maybe_inputs = SplitInputs(Data, Size);
				if (!maybe_inputs) {
				return 0;
				}
				auto inputs = std::move(maybe_inputs.value());

				struct bdiff_line a, b;
				int an = bdiff_splitlines(inputs.left.get(), inputs.left_size, &a);
				int bn = bdiff_splitlines(inputs.right.get(), inputs.right_size, &b);
				struct bdiff_hunk l;
				bdiff_diff(a, an, b, bn, &l);
				free(a);
				free(b);
				bdiff_freehunks(l.next);
				return 0; // Non-zero return values are reserved for future use.
				}

				#ifdef HG_FUZZER_INCLUDE_MAIN
				int main(int argc, char **argv)
				{
				const char data[] = "asdf";
				return LLVMFuzzerTestOneInput((const uint8_t *)data, 4);
				}
				#endif

				} // extern "C"