Add raw memory visualization tool to redbean

This change introduces a `-W /dev/pts/1` flag to redbean. What it does
is use the mincore() system call to create a dual-screen terminal
display that lets you troubleshoot the virtual address space. This is
useful since page faults are an important thing to consider when using a
forking web server. Now we have a colorful visualization of which pages
are going to fault and which ones are resident in memory.

The memory monitor, if enabled, spawns as a thread that just outputs
ANSI codes to the second terminal in a loop. In order to make this
happen using the new clone() polyfill, stdio is now thread safe.

This change also introduces some new demo pages to redbean. It also
polishes the demos we already have, to look a bit nicer and more
presentable for the upcoming release, with better explanations too.
This commit is contained in:
Justine Tunney 2022-05-14 04:33:58 -07:00
parent 578cb21591
commit 80b211e314
106 changed files with 1483 additions and 592 deletions

View file

@ -2,6 +2,7 @@
vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi
*/
#define LOCALTIME_IMPLEMENTATION
#include "libc/bits/bits.h"
#include "libc/calls/calls.h"
#include "libc/intrin/spinlock.h"
#include "libc/str/str.h"
@ -241,50 +242,12 @@ ttunspecified(struct state const *sp, int i)
return memcmp(abbr, UNSPEC, sizeof UNSPEC) == 0;
}
static int_fast32_t
detzcode(const char *const codep)
{
register int_fast32_t result;
register int i;
int_fast32_t one = 1;
int_fast32_t halfmaxval = one << (32 - 2);
int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
int_fast32_t minval = -1 - maxval;
result = codep[0] & 0x7f;
for (i = 1; i < 4; ++i)
result = (result << 8) | (codep[i] & 0xff);
if (codep[0] & 0x80) {
/* Do two's-complement negation even on non-two's-complement machines.
If the result would be minval - 1, return minval. */
result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
result += minval;
}
return result;
forceinline int_fast32_t detzcode(const char *const codep) {
return READ32BE(codep);
}
static int_fast64_t
detzcode64(const char *const codep)
{
register int_fast64_t result;
register int i;
int_fast64_t one = 1;
int_fast64_t halfmaxval = one << (64 - 2);
int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
result = codep[0] & 0x7f;
for (i = 1; i < 8; ++i)
result = (result << 8) | (codep[i] & 0xff);
if (codep[0] & 0x80) {
/* Do two's-complement negation even on non-two's-complement machines.
If the result would be minval - 1, return minval. */
result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
result += minval;
}
return result;
forceinline int_fast64_t detzcode64(const char *const codep) {
return READ64BE(codep);
}
static void