Mercurial > hg
view mercurial/exewrapper.c @ 34880:9e18ab7f7240
sparse-read: move from a recursive-based approach to a heap-based one
The previous recursive approach was trying to optimise each read slice to have
a good density. It had the tendency to over-optimize smaller slices while
leaving larger hole in others.
The new approach focuses on improving the combined density of all the reads,
instead of the individual slices. It slices at the largest gaps first, as they
reduce the total amount of read data the most efficiently.
Another benefit of this approach is that we iterate over the delta chain only
once, reducing the overhead of slicing long delta chains.
On the repository we use for tests, the new approach shows similar or faster
performance than the current default linear full read.
The repository contains about 450,000 revisions with many concurrent
topological branches. Tests have been run on two versions of the repository:
one built with the current delta constraint, and the other with an unlimited
delta span (using 'experimental.maxdeltachainspan=0')
Below are timings for building 1% of all the revision in the manifest log using
'hg perfrevlogrevisions -m'. Times are given in seconds. They include the new
couple of follow-up changeset in this series.
delta-span standard unlimited
linear-read 922s 632s
sparse-read 814s 566s
author | Boris Feld <boris.feld@octobus.net> |
---|---|
date | Wed, 18 Oct 2017 12:53:00 +0200 |
parents | 31c6c4d27be7 |
children | aca727359ec5 |
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/* exewrapper.c - wrapper for calling a python script on Windows Copyright 2012 Adrian Buehlmann <adrian@cadifra.com> and others This software may be used and distributed according to the terms of the GNU General Public License version 2 or any later version. */ #include <stdio.h> #include <windows.h> #include "hgpythonlib.h" #ifdef __GNUC__ int strcat_s(char *d, size_t n, const char *s) { return !strncat(d, s, n); } int strcpy_s(char *d, size_t n, const char *s) { return !strncpy(d, s, n); } #endif static char pyscript[MAX_PATH + 10]; static char pyhome[MAX_PATH + 10]; static char envpyhome[MAX_PATH + 10]; static char pydllfile[MAX_PATH + 10]; int main(int argc, char *argv[]) { char *p; int ret; int i; int n; char **pyargv; WIN32_FIND_DATA fdata; HANDLE hfind; const char *err; HMODULE pydll; void(__cdecl * Py_SetPythonHome)(char *home); int(__cdecl * Py_Main)(int argc, char *argv[]); if (GetModuleFileName(NULL, pyscript, sizeof(pyscript)) == 0) { err = "GetModuleFileName failed"; goto bail; } p = strrchr(pyscript, '.'); if (p == NULL) { err = "malformed module filename"; goto bail; } *p = 0; /* cut trailing ".exe" */ strcpy_s(pyhome, sizeof(pyhome), pyscript); hfind = FindFirstFile(pyscript, &fdata); if (hfind != INVALID_HANDLE_VALUE) { /* pyscript exists, close handle */ FindClose(hfind); } else { /* file pyscript isn't there, take <pyscript>exe.py */ strcat_s(pyscript, sizeof(pyscript), "exe.py"); } pydll = NULL; p = strrchr(pyhome, '\\'); if (p == NULL) { err = "can't find backslash in module filename"; goto bail; } *p = 0; /* cut at directory */ /* check for private Python of HackableMercurial */ strcat_s(pyhome, sizeof(pyhome), "\\hg-python"); hfind = FindFirstFile(pyhome, &fdata); if (hfind != INVALID_HANDLE_VALUE) { /* Path .\hg-python exists. We are probably in HackableMercurial scenario, so let's load python dll from this dir. */ FindClose(hfind); strcpy_s(pydllfile, sizeof(pydllfile), pyhome); strcat_s(pydllfile, sizeof(pydllfile), "\\" HGPYTHONLIB ".dll"); pydll = LoadLibrary(pydllfile); if (pydll == NULL) { err = "failed to load private Python DLL " HGPYTHONLIB ".dll"; goto bail; } Py_SetPythonHome = (void *)GetProcAddress(pydll, "Py_SetPythonHome"); if (Py_SetPythonHome == NULL) { err = "failed to get Py_SetPythonHome"; goto bail; } Py_SetPythonHome(pyhome); } if (pydll == NULL) { pydll = LoadLibrary(HGPYTHONLIB ".dll"); if (pydll == NULL) { err = "failed to load Python DLL " HGPYTHONLIB ".dll"; goto bail; } } Py_Main = (void *)GetProcAddress(pydll, "Py_Main"); if (Py_Main == NULL) { err = "failed to get Py_Main"; goto bail; } /* Only add the pyscript to the args, if it's not already there. It may already be there, if the script spawned a child process of itself, in the same way as it got called, that is, with the pyscript already in place. So we optionally accept the pyscript as the first argument (argv[1]), letting our exe taking the role of the python interpreter. */ if (argc >= 2 && strcmp(argv[1], pyscript) == 0) { /* pyscript is already in the args, so there is no need to copy the args and we can directly call the python interpreter with the original args. */ return Py_Main(argc, argv); } /* Start assembling the args for the Python interpreter call. We put the name of our exe (argv[0]) in the position where the python.exe canonically is, and insert the pyscript next. */ pyargv = malloc((argc + 5) * sizeof(char *)); if (pyargv == NULL) { err = "not enough memory"; goto bail; } n = 0; pyargv[n++] = argv[0]; pyargv[n++] = pyscript; /* copy remaining args from the command line */ for (i = 1; i < argc; i++) pyargv[n++] = argv[i]; /* argv[argc] is guaranteed to be NULL, so we forward that guarantee */ pyargv[n] = NULL; ret = Py_Main(n, pyargv); /* The Python interpreter call */ free(pyargv); return ret; bail: fprintf(stderr, "abort: %s\n", err); return 255; }