From 085cb2517b98cea23aa5ec5f57e1022bf4653616 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Tue, 1 Jan 2019 13:03:08 +0000 Subject: use buffered stdio (lightly tested) Our generation of HTML triggers many small write(2) syscalls which is inefficient. Time output on a horrible query against my git.git mirror shows significant performance improvement: QUERY_STRING='id=2b93bfac0f5bcabbf60f174f4e7bfa9e318e64d5&id2=d6da71a9d16b8cf27f9d8f90692d3625c849cbc8' PATH_INFO=/mirrors/git.git/diff export QUERY_STRING PATH_INFO time ./cgit >/dev/null Before: real 0m1.585s user 0m0.904s sys 0m0.658s After: real 0m0.750s user 0m0.666s sys 0m0.076s --- filter.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) (limited to 'filter.c') diff --git a/filter.c b/filter.c index 70f5b74..fba26aa 100644 --- a/filter.c +++ b/filter.c @@ -48,6 +48,7 @@ static int open_exec_filter(struct cgit_filter *base, va_list ap) for (i = 0; i < filter->base.argument_count; i++) filter->argv[i + 1] = va_arg(ap, char *); + chk_zero(fflush(stdout), "unable to flush STDOUT"); filter->old_stdout = chk_positive(dup(STDOUT_FILENO), "Unable to duplicate STDOUT"); chk_zero(pipe(pipe_fh), "Unable to create pipe to subprocess"); @@ -71,6 +72,7 @@ static int close_exec_filter(struct cgit_filter *base) struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base; int i, exit_status = 0; + chk_zero(fflush(stdout), "unable to flush STDOUT"); chk_non_negative(dup2(filter->old_stdout, STDOUT_FILENO), "Unable to restore STDOUT"); close(filter->old_stdout); @@ -143,17 +145,32 @@ void cgit_init_filters(void) #endif #ifndef NO_LUA -static ssize_t (*libc_write)(int fd, const void *buf, size_t count); +static size_t (*libc_fwrite)(const void *buf, size_t size, size_t n, FILE *); +static ssize_t (*libc_write)(int fd, const void *buf, size_t size); static ssize_t (*filter_write)(struct cgit_filter *base, const void *buf, size_t count) = NULL; static struct cgit_filter *current_write_filter = NULL; void cgit_init_filters(void) { + /* + * we need to wrap both functions since the Lua filter may + * have code which calls write(2) directly, bypassing fwrite(3) + */ + libc_fwrite = dlsym(RTLD_NEXT, "fwrite"); + if (!libc_fwrite) + die("Could not locate libc's write function"); libc_write = dlsym(RTLD_NEXT, "write"); if (!libc_write) die("Could not locate libc's write function"); } +size_t fwrite(const void *buf, size_t size, size_t n, FILE *f) +{ + if (f != stdout || !filter_write) + return libc_fwrite(buf, size, n, f); + return filter_write(current_write_filter, buf, size * n); +} + ssize_t write(int fd, const void *buf, size_t count) { if (fd != STDOUT_FILENO || !filter_write) @@ -305,6 +322,9 @@ static int open_lua_filter(struct cgit_filter *base, va_list ap) struct lua_filter *filter = (struct lua_filter *)base; int i; + if (fflush(stdout)) + return 1; + if (init_lua_filter(filter)) return 1; -- cgit v1.2.3-24-ge0c7