58b2353ba
Denys Vlasenko
2025-08-05
Subject
top: improve response time to keyboard input
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
procps/top.c+27 -14
| @@ -968,7 +968,7 @@ enum { | |
| | PSSCAN_SMAPS | |
| | PSSCAN_COMM, | |
| EXIT_MASK = 0, | |
| - | NO_RESCAN_MASK = (unsigned)-1, |
| + | ONLY_REDRAW = (unsigned)-1, |
| }; | |
| #if ENABLE_FEATURE_TOP_INTERACTIVE | |
| @@ -984,12 +984,19 @@ static unsigned handle_input(unsigned scan_mask, duration_t interval) | |
| int32_t c, cc; | |
| c = safe_read_key(STDIN_FILENO, G.kbd_input, interval * 1000); | |
| - | if (c == -1 && errno != EAGAIN) { |
| - | /* error/EOF */ |
| - | option_mask32 |= OPT_EOF; |
| + | if (c == -1) { |
| + | if (errno != EAGAIN) |
| + | /* error/EOF */ |
| + | option_mask32 |= OPT_EOF; |
| + | /* else: timeout - rescan and refresh */ |
| break; | |
| } | |
| interval = 0; | |
| + | /* "continue" statements below return to do one additional |
| + | * quick attempt to read a key. This prevents |
| + | * long sequence of e.g. "nnnnnnnnnnnnnnnnnnnnnnnnnn" |
| + | * to cause lots of rescans. |
| + | */ |
| if (c == initial_settings.c_cc[VINTR]) | |
| return EXIT_MASK; | |
| @@ -1023,7 +1030,7 @@ static unsigned handle_input(unsigned scan_mask, duration_t interval) | |
| G_scroll_ofs = ntop - 1; | |
| if (G_scroll_ofs < 0) | |
| G_scroll_ofs = 0; | |
| - | return NO_RESCAN_MASK; |
| + | return ONLY_REDRAW; |
| } | |
| cc = c; | |
| @@ -1083,7 +1090,7 @@ static unsigned handle_input(unsigned scan_mask, duration_t interval) | |
| if (c == 's') { | |
| sort_field = (sort_field + 1) % NUM_SORT_FIELD; | |
| if (scan_mask == TOPMEM_MASK) | |
| - | return NO_RESCAN_MASK; |
| + | return ONLY_REDRAW; |
| scan_mask = TOPMEM_MASK; | |
| free(prev_hist); | |
| prev_hist = NULL; | |
| @@ -1093,7 +1100,7 @@ static unsigned handle_input(unsigned scan_mask, duration_t interval) | |
| # endif | |
| if (c == 'r') { | |
| inverted ^= 1; | |
| - | continue; |
| + | return ONLY_REDRAW; |
| } | |
| # if ENABLE_FEATURE_TOP_SMP_CPU | |
| /* procps-2.0.18 uses 'C', 3.2.7 uses '1' */ | |
| @@ -1115,8 +1122,8 @@ static unsigned handle_input(unsigned scan_mask, duration_t interval) | |
| } | |
| # endif | |
| # endif | |
| - | break; /* unknown key -> force refresh */ |
| - | } |
| + | /* Unknown key. Eat remaining buffered input (if any) */ |
| + | } /* while (1) */ |
| return scan_mask; | |
| } | |
| @@ -1253,7 +1260,7 @@ int top_main(int argc UNUSED_PARAM, char **argv) | |
| #endif | |
| while (scan_mask != EXIT_MASK) { | |
| - | IF_FEATURE_TOP_INTERACTIVE(unsigned new_mask;) |
| + | IF_FEATURE_TOP_INTERACTIVE(unsigned new_mask = scan_mask;) |
| procps_status_t *p = NULL; | |
| if (OPT_BATCH_MODE) { | |
| @@ -1337,7 +1344,7 @@ int top_main(int argc UNUSED_PARAM, char **argv) | |
| qsort(topmem, ntop, sizeof(topmem_status_t), (void*)topmem_sort); | |
| } | |
| #endif | |
| - | IF_FEATURE_TOP_INTERACTIVE(display:) |
| + | IF_FEATURE_TOP_INTERACTIVE(redraw:) |
| IF_FEATURE_TOPMEM(if (scan_mask != TOPMEM_MASK)) { | |
| display_process_list(G.lines, col); | |
| } | |
| @@ -1353,9 +1360,15 @@ int top_main(int argc UNUSED_PARAM, char **argv) | |
| clearmems(); | |
| sleep_for_duration(interval); | |
| #else | |
| - | new_mask = handle_input(scan_mask, interval); |
| - | if (new_mask == NO_RESCAN_MASK) |
| - | goto display; |
| + | new_mask = handle_input(scan_mask, |
| + | /* After "redraw with no rescan", have one |
| + | * key timeout shorter that normal |
| + | * (IOW: rescan sooner): |
| + | */ |
| + | (new_mask == ONLY_REDRAW ? 1 : interval) |
| + | ); |
| + | if (new_mask == ONLY_REDRAW) |
| + | goto redraw; |
| scan_mask = new_mask; | |
| clearmems(); | |
| #endif | |